New to Cooling

Hey Guys

I recently received a gaming PC from a respectable PC Company. The rig it self has the H100i v2 cooling system installed.

I just wanted to make sure i was understand everything that was being shown too me on the Corsair Link. As i said I'm new to this sort of cooling.

I have set the profile to Quiet and the FAN rpm is sitting at 1260 with the Pump at 1920 with the CPU sitting idle between 35-40 degree's and the motherboard at 17 degree's.

Question 1) Due to the heat in the UK at the moment are these temperatures and RPM sound about right? I've put the profile to performance as well and to be honest i don't see a vast improvement in temperature to warrant the boost (however not tested with gaming yet). Also is the temperature that is allocated next to the FAN RPM AND PUMP RPM, is that the temperature of the water? and I'm i right in saying if the outside air (room temp) is hot, then the water will be hotter as well?

Question 2) My motherboard is a Aorus Ultra Gaming CF board made by Gigabyte. I'm i right in saying when i go onto Corsair Link, the MB fan is the Motherboard Fan? and is this the fan on the motherboard itself or the fan on top off or back of the case? - Currently at the moment it's spinning at 956RPM but does drop to 700, it use to run even lower, however to get the RPM for the H100iv2 to work i had to go into the bios and change the CPU-FAN to run at 100% could this of had an impact on this? Also are those speeds ok for that fan? and if not how do i control them as the Corsair Link will not let me.

I just wanted to make sure everything was ok and i was not stressing the PC to much. Also i would like to keep the profile to Quiet as the fans seem loud if i set it to balance or performance. Under gaming would this be ok? - to keep as quiet.

I hope this makes sense and any information will be great.

Thank you :)

1) Those temps sound about right. What's the coolant temperature? Yes, that's the coolant temperature listed in Link/iCue for the H100iV2 temperature.

And I wouldn't necessarily think that the motherboard temp reading is correct ... 17C is pretty chilly for ambient temperature. Your case's interior is going to be warmer than your room's ambient temperature so that temp reading just doesn't compute. And yes, the warmer the ambient environment, the warmer the coolant will be. Can't around those pesky laws of thermodynamics, unfortunately.

2) MB Fan will be one of probably several motherboard fans. It's fun, sometimes, to guess which is which. Once you figure it out, I suggest labeling them with a descriptive name. That fan listed is connected to the motherboard ... where it is I can't say. That will depend on where they installed it. If you carefully stop the fan, you'll be able to tell where it's showing up in Link. Good call, by the way, to set that header to 100%. The fan header that the cooler is connected to has to be set to that or it won't work properly; that's why you were seeing variable pump speeds. The pump speeds will be static (~2000 RPM for quiet, ~3000 RPM for performance) and the CPU_FAN header will read approximately 1/2 of the actual pump speed.

The fan speeds with the default profiles will vary by the coolant temperature. That's right and proper. Is Quiet mode good enough for gaming? Hard to say as that'll be based on your own criteria for "good enough" as well as other factors (like GPU heat). That said, the stock fans do make a 737 sound quiet. I replaced mine with MLs and was much, much happier with them.

Have a read through of the Liquid Cooler FAQ as well. It may be helpful.

Thank you so much for your feedback.

Well under the BIOS the fans were labelled as Pump, Fan 1 etc but none of them in full worked but CPU FAN did and that's how I got my rpm. Apparently its something to do with the pump getting the 12v its needs, but was worried if it was at 100% it would burn out. So I'm I right in doing what I did?

Yeah 17 degrees doesn't sound right but even PC speccy was showing 17. Plus should I be concerned the LINK is not picking up my SSD or HDD? Although they work fine.

Finally what temperature should my water cooler be at under gaming ?, at the moment its sat at 32 with my cpu downloading games and browsing is that ok?

Finally is there any advantage to having the fans set to quiet or and pump set to performance or vica versa?

Sorry for all the questions :) but I do appreciate it

Well under the BIOS the fans were labelled as Pump, Fan 1 etc but none of them in full worked but CPU FAN did and that's how I got my rpm. Apparently its something to do with the pump getting the 12v its needs, but was worried if it was at 100% it would burn out. So I'm I right in doing what I did?

In the BIOS, those labels Pump, Fan 1, etc. will refer to specific fan headers with that label. The labels can be really hard to read on the motherboard. Sometimes it is easier to look at your motherboard specification sheet, owner's manual, or something on their website to narrow the location and get a better sense of where they are at.

Yes, you did the right thing and undervolting pump is more likely to make it wear out. Regardless, you can adjust the pump speed, just use the software (Link or iCUE) to do it. Those 12v are needed to make the pump, fans, and lights run. You should be fine at the lower speed and that is what I use as well. I run a very high overclock and pump speed is not a meaningful factor on 4/6 core CPUs and AIO coolers.

Yeah 17 degrees doesn't sound right but even PC speccy was showing 17. Plus should I be concerned the LINK is not picking up my SSD or HDD? Although they work fine.

The 17C is a glitch and not a real value. Temp #5 is common on many boards and I am not sure we know what it supposed to be. In Link this will usually be 0C or 127C. It may be an empty value and the program is sticking a number there to fill the place. Either way, just ignore it. Unfortunately, Link and iCUE are not the best at measuring specific motherboard sensor values like PCH Temp, VRM temp, etc. Duplicate values are also common.

Finally what temperature should my water cooler be at under gaming ?, at the moment its sat at 32 with my cpu downloading games and browsing is that ok?

The range I usually give is coolant temp (H100i v2 Temp) will run about 4-7C above your room temperature when at idle in a relaxed state. Small cases or disabled power saving features tend to move you a little higher in the range. I am not sure what CPU you have, but it seems likely to be a Kaby (7600/7700) or Coffee Lake (8600/8700) 95 watt TDP model. Most people will a further coolant rise of about +6C at 100% CPU load. It is possible to see more than when gaming, particularly with a big GPU and/or small case. The GPU heats the case up as much as anything else. That makes it hard to give you a precise value, but if you see the H100i v2 Temp go up more than +10C while gaming, then there are questions to ask or maybe some heat management things to look at. Coolant temp tends to change slowly. You may drop 3-5C really quick when you stop the load, but those last few degrees often take much longer, especially if the case temp has gone up. The motherboard sensor is probably the best thing to match against the coolant temp to see if things are in step when idle.

Finally is there any advantage to having the fans set to quiet or and pump set to performance or vica versa?

As above, I would set the pump to the lower speed and leave it. Feel free to experiment as much as you like, but most people eventually come to the conclusion any difference in performance is negligible but the pump can be heard easily at the highest speed. As for fans, they only affect the coolant temperature, not the CPU temp directly. If the coolant is only +2C, then even at max fan speed you can only bring the CPU down 2C. Usually not worth the noise. I would let sound be your guide unless you are having CPU temp problems. Slow and steady on the fans works just fine in a water cooled system. The presets (Quiet/Balanced/Extreme) all have hidden temperature control points. I am not sure any of us have taken the time to figure it out. You most certainly can use Quiet when on the desktop. In the UK, you might be able to use that comfortably (sound) all year. In the south of Spain in a 32C room, Quiet will very loud at the desktop with zero load. Most people are better off making their own custom curves. My general advice is to pick the highest fan speed you can stand, then set that to just above the highest coolant temp you normally see. That might take a little time to figure out, but then you can use the fans as an audio warning. Hmm... why are they so loud right now. I see.. very hot today, etc. Small differences in fan speed make little difference in coolant temperature. If 1400 rpm seems loud and 1300 seems much better, absolutely use 1300.

Thank you again for your post.

For the time being I have left the profile to balanced and the fan and pump speeds to quiet. As for some reason if I select quiet as the profile everything sounds louder :bigeyes: which makes no sense.

I have a NXT s340 elite case I think and the radiator is mounted vertically near my GPU I believe. With big fan on top of case. Yes my cpu is a 8600k.

OK, so if its a S340, the only place to put a 240mm radiator is right against the front rail. I am very sure they set the fans to intake, forcing air into the case through the radiator. Then there are single fans in the top and rear slot for exhaust. As far as cooling the CPU, this changes nothing. However, those front radiator fans are the only supply of air into the case and if you were to keep them very low, you might see slightly higher internal case temperatures (motherboard, GPU, etc.). That does not mean I think you should turn them up high when you game. No matter what you do, you cannot damage your components by choosing low when you should have chosen high, or vice versa. All of these things are about fine tuning temperatures and noise.

I am not sure about the louder on quiet aspect. Sometimes certain fans have a weird RPM were they are irritating, maybe around a specific motor pole point. Regardless, I think you should just enjoy it for a while and not overthink any of this. Keep on a casual eye on general behavior and temp ranges. You can always come back and ask questions.

Ok so ive tried them both now.

Quiet Profile with Quiet Mode set on both I get 900 rpm on fan and 1800 on pump.

However if I set the profile to balance and the same quiet mode on both I get virtually the same.

So what is the difference between profile and mode ? Whats the point in having a balance profile if you can set the mode to quiet doesnt make sense to me.

Sorry to be a pain

OK, so if its a S340, the only place to put a 240mm radiator is right against the front rail. I am very sure they set the fans to intake, forcing air into the case through the radiator. Then there are single fans in the top and rear slot for exhaust. As far as cooling the CPU, this changes nothing. However, those front radiator fans are the only supply of air into the case and if you were to keep them very low, you might see slightly higher internal case temperatures (motherboard, GPU, etc.). That does not mean I think you should turn them up high when you game. No matter what you do, you cannot damage your components by choosing low when you should have chosen high, or vice versa. All of these things are about fine tuning temperatures and noise.

 

I am not sure about the louder on quiet aspect. Sometimes certain fans have a weird RPM were they are irritating, maybe around a specific motor pole point. Regardless, I think you should just enjoy it for a while and not overthink any of this. Keep on a casual eye on general behavior and temp ranges. You can always come back and ask questions.

Thank you for the post and you describe my case perfectly. I think I will leave it all on balance and see how I get on but leave the mode on quiet.

So what is the difference between profile and mode ? Whats the point in having a balance profile if you can set the mode to quiet doesnt make sense to me.

I am not sure exactly what you're asking, but... Your profiles are the list of settings on the left side of the iCUE or Link application. These can include a large number of things. Each and every Corsair device that is iCUE capable, with have its own settings. So, if you have a Corsair mouse, keyboard, and water cooler like the H100i v2, you will see each device in iCUE and each will have its own settings. The collective total of all of those things are saved as a profile, which you can rename. Incidentally, the "Default" profile has no special meaning or value. Whichever profile is on the top of the list will be the actual default profile. You can rename these. So, I could make a profile called "Game" and have it set with higher fan speeds appropriate for gaming. You could then make another profile called Quiet Work with really low fan speeds. Now for you, if you just have the one Corsair device (H100i v2), it really doesn't matter. You can do the exact same thing inside the cooler Performance Tab by hitting + and making a pile of different fan curves. The advantage of a profile over the "mode change" is you can probably change things faster. Open CUE, right there on main menu click Game and fans speed up. Again with just the cooler, it's only a few clicks more to go into the Performance Tab and apply a different fan curve to the H100i v2 fans. Still, faster is faster. *(Actually, you might want to drag the Game profile to the top to make it active. Drag Quiet back to the top to reverse it. You can also do this automatically by linking your game .exe files to the GAME profile. That will make the change automatic and it will go back to quiet when you quit the game.)

The profiles become much more important when you throw RGB into this stuff. Most of my profiles are all thematic lighting and have nothing to do with fan speeds. I copy the same fan curve to all of them as needed.

As for specific fan speeds on Quiet vs Balanced, you may definitely find the end fan speed is the same at certain temperatures on the lower end. The quiet should have a lower maximum speed. If you are sitting on the desktop, you probably won't notice much difference until the coolant temp goes past 30C.

Ok so ive tried them both now.

 

Quiet Profile with Quiet Mode set on both I get 900 rpm on fan and 1800 on pump.

 

However if I set the profile to balance and the same quiet mode on both I get virtually the same.

 

So what is the difference between profile and mode ? Whats the point in having a balance profile if you can set the mode to quiet doesnt make sense to me.

 

Sorry to be a pain

Not being a pain at all; this is what the forum is for.

The difference between the modes, for the fans, will be at what temperature they ramp up speed and how high they ramp up. IIRC, Quiet mode doesn't go over 60% fan, Balanced goes up to 80% and Performance goes to 100%, at which point you'll be looking around for a plane about to take off.

In all honestly, you'll get diminishing returns over 80% and quite possible even lower, especially with the radiators on intake. c-attack's comment on case temps is worth thinking about however, especially if you notice your GPU temps getting high during a gaming session.

On the pump speeds, I've not seen any difference in performance at all with performance vs quiet.

Ah I get you, so profile is just what links it all together.

Could I.not just leave the fans as quiet but alter the curve so they kick in at higher temps. What do you mean by diminishing returns? So anything over 80% is waste of time?

Would you recommend leaving pump as quiet in gaming or performace as Ive heard two different stories.

Ah I get you, so profile is just what links it all together.

Could I.not just leave the fans as quiet but alter the curve so they kick in at higher temps. What do you mean by diminishing returns? So anything over 80% is waste of time?

 

Would you recommend leaving pump as quiet in gaming or performace as Ive heard two different stories.

Yes, the profile is just a group of settings that you apply together. You can set a custom fan curve if you like ... many folks do ... that does exactly that.

And I'm sure that there are cases where more than 80% fan helps performance. I never saw a difference, personally. So yeah, that's what I mean ... more air doesn't cool the radiator any better. You can only dissipate so much heat at a time. Pesky laws of thermodynamics again.

As for the pump ... doesn't matter, really. With the H100i V2, I never saw a difference in cooling between the two speeds. Different story completely with the Pro series coolers tho.

Could I.not just leave the fans as quiet but alter the curve so they kick in at higher temps.

Absolutely, but you cannot alter the Quiet/Balanced/Extreme Preset. If using iCUE, click the "+" in the performance tab and then set that curve exactly how you want it. This is what I recommend for nearly everyone.

What do you mean by diminishing returns? So anything over 80% is waste of time?

The relationship between fan speed and coolant temperature delta (change up or down) is not linear. If you could double your fan speed and half your CPU temp, that would be fantastic! It doesn't work that way. When at lower speeds, you will see noticeable differences between say 500 and 1000 rpm. As the speeds get really fast, you are already expelling about as much heat as you can off the radiator. You would likely see zero temperature difference between 2500 and 3000 rpm. With all of these recent CPUs, the voltage on the pins and the CPU construction is the limiting factor. No matter what kind of cooler you have, eventually a higher voltage will make the CPU temp too hot and the physical heat transmission between CPU and cold plate is not enough to prevent reaching critical temperatures. Long way of saying voltage matters a lot more than fan speed for CPU temps.

Would you recommend leaving pump as quiet in gaming or performace as Ive heard two different stories.

I have to phrase this carefully since I am not sure how iCUE displays this information. The brand new H115i Pro and H150i Pro cooler have 3 possible fixed pump speeds. All other coolers, like the H100i v2 only have 2 speeds. While the iCUE interface has three potential settings, only 2 of those will be selectable for you. I cannot remember which one of the "presets" is blocked off for your cooler. Essentially, you have a low and high speed. Low is 1800-2000. High is around 2700-3000. You only need the low. So if the lowest setting is Quiet, use that. If that is Balanced, click that. The pump cycle rate does not often affect AIO coolers with relatively short hoses and free flowing systems. I use 2100 on my 8700K. I get zero temp change by using the 3000 rpm speed. I can most certainly hear the pump at 3000 rpm. Easy decision.

I just use Link, never heard of Icue if Im honest with you. But thank you for all your input. So what temperature should I aim the water cool temp to be at say playing a game like Witcher 3 on max settings 1080p.

And if you were to set a curve for a fan, what temp / percentage would you set them at, just to give myself a building block for when gaming.

Link was the prior control software for internal devices, like coolers and fans. CUE was the control software for peripherals, like keyboards and mice. Then very recently those two aspects were merged into one program called iCUE. With just the H100i v2, there is no reason you need to change the software to iCUE. In fact, you might be better off with Link. You can easily change your profile (and thus fan curves) by clicking the drop down < in the task bar. I guess we should have clarified which software you were on at the beginning (or I missed it). No matter for performance or choices, but some of the instructions or descriptions I gave were for iCUE.

In Link, two pump speeds. Balanced and Performance. Balanced is all you need, but again, feel free to experiment as much as you like.

I would figure out what speed is "too loud" for gaming. I use headphones and 1500 is pretty much my limit. If I figure out that 37C is the about the highest coolant temp I ever see, I would then set 1500 rpm to just above that temp, maybe at 39 or 40C. At the low end, you can go as slow as you like. You might see a +2 difference in coolant temp at 500 vs 1000, but it really doesn't matter when the CPU temp is 30-40C. I would pick something you don't really notice, maybe try around 750-800 and tweak from there. Your baseline temp should room temp +4-6C or the normal resting coolant temp. All the points in between don't really matter. Just make a nice smooth curve that doesn't alarm you. In contract, I do like to put a spike past my normal coolant range. If I never break 40C, I might put a really high fan speed at 43-45C to let me know if my temps get way out of range. You will hear the fans without having to stare at a CPU temp.

From what I remember, Witcher 3 was very well optimized for the CPU. I don't think you will see a lot of excess CPU heat. You will see GPU heat. Any medium, comfortable, non-irritating fan speed should do.

Do you mean the two pump speeds are Quiet and Performance? And to just leave it as quiet ?

Thank you

Do you mean the two pump speeds are Quiet and Performance? And to just leave it as quiet ?

 

Thank you

Yes, that is my recommendation and it is a rare day when someone reports a meaningful difference in coolant temperature between the two speeds. However just like everything else, this is definitely user preference and feel free to try both in whatever situations you like. If you can't hear it on the higher setting, then that is a bonus. Otherwise, you get the same cooling with less noise on Quiet.

Hi Guys

So I'm back again and recently turned on my PC after this hot weather. I've got both my pump and fan set to quiet. However when sat idle the fans still reach 1245rpm with temperature of the cpu being between 37-43. Literally all I'm doing is downloading games on Steam. Surely this is high? Or I'm I losing the plot as I'm sure my air cooled CPU was lower then this when idle.

Current temp in UK is around 24-26 at moment.

Time to move on to custom fan curves. Even in Northern climates, there are going to be some warm days where the fan speed becomes annoying on the presets meant for a 20-23 room. The fans respond to coolant temperature. What is the H100i v2 Temp (coolant temperature) now?

If your room is climbing into the upper 20s, then the baseline for the cooler is going to be low 30s. That is as low as you can go in Summer, but likely beyond the peak value you'll see in Winter. You have to make some seasonal adjustments. My general recommendation is to set the highest fan speed you can tolerate just above your normal peak coolant temp. Summer time + GPU heat probably means that will be somewhere around 40-42C for you, but take note of the coolant temp in Link after a long session. As for the other end, figure out your baseline (likely 27-30C this time of year) and set the fans as low as you want. Even in a highly optimized case, I also need to use seasonal fan curves. Just keep in mind the starting coolant temp when you power on (and the case internal temperature) is as low as you can go. No reason to blast the fans.

CPU air coolers work the same, except with no other viable variable they get set to CPU temperature. We get accustomed to equating fan speed with current work load, but that's not really how it works. Both types of coolers physically transmit heat from the CPU lid to somewhere else. For the water cooling system, that's the radiator exhaust. For the air tower, that's whatever radiator is bolted to it. The big difference is the water system can take a lot more heat in the short terms without needing to immediately expel it. The fans don't have to react to load. Slow and steady works fine.

What is your fan speed "irritant level"? For me, it is usually around 1500 rpm for 120mm fans. That is as loud as I can stand at load and probably with headphones. Everyone is different and every case environment is different as well, not to mention the fans themselves. Figure out your max tolerance, then set that speed to maybe 1-2C above the highest H100i v2 Temp you have ever seen on your system. That should ensure you only hit the tolerance cap on a really hot day or a really long, sustained load.

The minimum is whatever you like. For me, 750 rpm sounds about like the air conditioning vent and completely unnoticeable without sticking my head in the case. Set your preferred minimum to something like 28-30C. Then straight line the other points between the low and high marks (or gradually build the line up). Use the next to last point for your "high" mark, saving the last one for an emergency alarm. Set the final point to 50C and something unmistakable, like 2000 rpm on the fans. You should never reach 50C for your set-up and environment. If you do, it probably means something isn't quite right with the pump. This will give you a clear warning things have gone amiss without needing to be chained to Link app watching temps.

Here is the thing to remember: +1C in coolant temperature = +1C in CPU temp. That's it. So when the coolant goes from 30 to 35C, your CPU will go up 5C - loaded or at idle. But it also means the reverse is true as well. Coolant at 35, blast those fans at 2000 rpm to bring it down to 33C -- you reduced your CPU temps by a whole 2C. That is almost never worth the noise unless you are right at the limit.

Thank you for your help.

So to make sure I understand,the fans kick in when the coolant hits a certain temp, not the cpu?

Correct. Think of the cooling in 3 stages.

Socket pins -> CPU - This is where the electricity is applied and the heat created.

CPU -> Heat spreader lid -> thermal paste -> cold plate on the cooler - This is how the heat gets out of the CPU. It's just material to material surface heat transference, like a pot on a stove burner. It doesn't matter whether there is air or water on the other side of the cold plate, the rate of heat transmission is defined by materials involved. Better transfer, less heat retained in the CPU and lower reported temperatures. A good example of this is "delidding" your CPU. A lot of 7700/8700K CPUs receive criticism for being really hot right out of the Intel box (and they are). A large part of the blame is given to the material Intel used to attach the heat spreader to the CPU. So people take off the heat spreader and put a better conducting material underneath, then put the lid back on. In an overclocked state, it takes about 25C off the end CPU temps from my 8700 and now delidding is becoming very popular. That is about the only thing you can do to address this part of the heat pathway.

Finally, Cooler Cold Plate -> water stream -> radiator fins -> out of your case - The cooler itself is just a dumping ground for the heat. Heat is picked up as each unit of water passes the cold plate, then released through the fins with the help of the fans before returning for another trip. Essentially, this part of the cooling system takes out the trash and dumps the heat elsewhere. At this point, the only influence the coolant has on the CPU cooling process is back at the cold plate. Heat transmission across a conductor is a two way street and will transfer both ways. So if the coolant is 35C, it will transfer heat back to a power-less CPU and make it 35C as well (at least on the top surface). Effectively then coolant temperature becomes the minimum possible CPU temperature and if you don't take out the trash (get rid of enough heat through the radiator), your CPU will slowly start to warm up. This takes time. At its best, the radiator can drop the coolant about 2C per pass through the radiator. Whether the coolant warms or cools is down to the amount of heat coming in versus heat going out.

For the most part, the CPU is always going to be warmer than the coolant. If you use higher c-states, adaptive voltage, and other standard power saving features, you can see your CPU temp sit right about the same level as the coolant. That all changes when the voltage comes back on. Intel has spent millions upon millions trying to make their power delivery extremely sophisticated and variable in its application. I am going to undo that and turn it back into a light bulb - on/off.

CPU OFF - No voltage at the pins, no heat. CPU the same as the coolant.

CPU ON - 1.xx volts applied at the pins, CPU will immediately jump up a very consistent +35-40-45C. The exact number is CPU and voltage dependent. My 8700K has a voltage on offset of +32-34C at 1.30v. This is a pretty low value because my processor has been delidded, but other than that, you can't change this.

Of course, the power delivery is more sophisticated and the load extremely variable. Your CPU will spend much of its time transitioning between those two states, thus rarely at the minimum and rarely at the maximum. However, the maximum offset also tells me how high I could let my coolant temperature go before I get into trouble. The cores would likely throttle around 90-95C, which means I would have to let my coolant get to 60C before I got into trouble. Now that's way past my generally conservative comfort zone and I prefer a lot less, but that is how it works. Your "voltage on" offset is probably more like 40C, but that also means your coolant temperature needs to get to 45-50C before you get into the caution zone in a worst case scenario.

So when you are idling at 35C and the coolant is 28C, that is the voltage between at the pins keeping the cores warm and in an operational state. You are not going to be at 0 volts. Most CPUs have a low end of around 0.65-0.75v in their default state. When you initiate a full 100% CPU load (like in a stress test or a badly optimized game launcher), you will see that big CPU core temp spike. The light just got turned on all the way and the voltage at the pins has spiked to 1.20-1.30v or the designated limit set in the BIOS. The heat must pass through the CPU to get to the exit and thus you see a big swing up in core temperatures. You can't change that number except by altering your voltage, but it helpful to know to understand what part of the total core temps is voltage induced (not changeable) and what part is addressable through the cooler. If you run a stress test you will see a big jump in CPU temps the moment you press start. Depending on the test, it will wiggle a little going down the line, but the "CPU Temp" usually holds comparatively steady. As the minutes tick by, you will likely see the CPU temp slowly rise, maybe 1C every minute. Compare that to the coolant temp. They are likely moving together. This is the effect of the cooler. +1C coolant temp = +1C CPU temp. So when we are talking about +5C coolant temperature changes, that only means 5C on the CPU. Most of the time, this doesn't matter and that is also why you can let the fans roll along comfortably, right until you get to your CPU temp limit.