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New at Water Cooling would like an education.


Raven0215
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Hello,

 

I've never water cooled before but have used AIO's for about 10 years or so and have really enjoyed the benefits of them(specifically Corsair Units). I am currently waiting for the Nvidia AMD Graphics cards to sort themselves out and will probably be picking up one flavor of those in the future not sure which yet.

 

I saw that several manufacturers are coming out with versions that will have an AIO built in but also some with water blocks where you can build your own cooling for them. Since Corsair has the Hydro X now I figured well maybe I will look into that.

 

I have been researching a lot and basically everything I have been seeing is whole systems where it is the CPU and graphics card etc in the Loop. Well I was thinking of just buying parts and water cooling one of the Graphics Cards that comes with the water block on it by itself since I already have an AIO on the CPU that I like.

 

Lets just use the 3080 or 6800XT Cards as an example. Originally I was thinking a 140mm Radiator but I see a lot of the AIO graphics card manufactuers are using 240mm Rads so I have space for a 280mm Radiator in my case so figured I would just use that along with the XD3 Pump/Reservoir and whatever tubing fittings etc I need. I don't really care about RGB Effects to be honest and I am not sure if using the XD5 would be of any benefit. I believe I would have room for it in my case if needed.

 

I Guess my main question is does this sound stupid, is it a waste of money, am I missing something? I would just like to get some opinions since my Water cooling knowledge is limited to only AIO at this point.

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Having two separate loops for CPU and GPU is a bit of a waste yes.

What size AIO do you currently have ?

 

The GPU is the component that produces the most heat, so it will benefit from having as much radiator space as possible. a 140mm rad is way too small. 280 is okay-ish.

 

Since the CPU doesn't need much when going custom loop, i'd rather have the AIO removed, and have CPU and GPU share the same loop. That allows to cool the GPU better. In most games, the GPU is taxed hard, and the CPU a lot less, so you would often have your AIO underutilized, and that one GPU radiator struggling to cool the card.

Going full custom loop allows to always have the most efficient use of all the radiator space you have.

 

Wether you go 3080 or 6800xt, that will be over 300W to dissipate just for the GPU. Usually that means a 360 rad. Adding the CPU on top will mean some more radiator space.

 

So, depending on what case you have, i'd suggest getting some combination of radiators to equal a 480 or better. like two 240, or two 280.. one 360+240..

You could get away with using less, but the cooler you keep the water, the higher the GPUs will be able to clock... and the slower you'll be able to run your fans for a more silent build.

 

regarding XD3 or XD5, it mostly comes down to space and noise.

XD3 uses a DDC pump that is less quiet than the D5 used on XD5. The smaller reservoir also means you'll take a lot longer to fill the loop.

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watercooling is a waste of money per se. but that aside, it's pretty fun lol

 

I don't think a seperate loop for GPU and CPU is a waste if you have the right hardware for that use case and if your case can properly support it. By having split loops you don't "waste" cooling capacity. Let's say you're gaming, the most heat getting put into the loop is by the GPU. The CPU only plays a minor role in that regard and by having that on an AIO potentially running at near silence, you have your full cooling potential reserved for your big boi GPU. But I do think, that only applies to the 3090s and their ridiculous power hunger. With a 300W 3080 or 6800XT, it probably doesnt matter at all if you CPU heat goes in there too with a full custom loop and I would rather prefer only having one pump as a potential point of failure than two pumps in that case.

 

That said, this of course only applies also with a proper case that has decent radiator support and airflow. As a rule of thumb, you'd want 120mm rad per 100W of heat output with some amount of overhead. So for a build with a 3080/6800XT you would potentially look at a 360mm rad minimum as LeDoyen already said, a bit more if you plan on overclocking. There is a diminishing return on radiators though so you probably are better off having decent airflow than cramming every place you can with a rad.

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Dual or multiple loops are more common in large cases or those with multiple GPUs. The advantage is each piece of hardware in the loop is only affected by its own heat rather than sharing a common pool. This is most useful in systems where one component is extremely large wattage like GPU(s) and the other is much smaller wattage. For example, if you had a Nvidia 3090 running a 400W VBios and paired it with a AMD 3700x (65w TDP), both components share the same coolant stream and the temperature of that coolant is the baseline temperature for both devices. This means the CPU suffers a temperature penalty because of the large wattage dumped into the system by the GPU. Even with multiple radiators and the CPU directly inline prior to the GPU, you can't take out all of the heat the GPU puts in on one pass through the radiators. Obviously this becomes true for virtually all CPUs if you are using multiple GPUs. The further apart the CPU and GPU are in terms of watts into the cooling system, the more the lesser component would benefit. Likewise the reverse is true and if both components have a similar load wattage, the difference between separate and combined systems are likely to be zero or hard to quantify.

 

There is another example of when dual cooling systems may benefit the user. The examples above assume that the disposal of heat from one radiator has no effect on the other. This is often not true. The most common example is standard mid/large tower case with room for one radiator on the front and one up top. The traditional orientation would be front intake radiator and top exhaust radiator, just as if you were running an air cooled case. The problem with this is the waste heat from the front radiator becomes intake air temp for the top. In effect, the top radiator becomes little more than a passenger with little to no coolant temp reduction. The intake air temp and coolant temp are already the same. One potential solution to this is to run both radiators as exhaust and try to draw air into the case from the rear/bottom. This is often called reverse flow. However, another way to deal with it is to set up a dual cooling system where the lower watt component (probably CPU) is the front intake and the heavy watt component (probably the GPU) is the top exhaust. So while the CPU system coolant is say 27C and its exhaust approximately the same, the GPU coolant is always going to be warmer than that and you still get a cooling effect while dumping the majority of the wattage directly out of the case (top radiator). That is what you would be aiming for in your current plans if you were to get a Hybrid water GPU model.

 

The irony of the above example is for quite a while we all put 280/360mm radiators (or as big as we can get) on our CPUs and GPU hybrid cooling was done on 120mm radiators. That would typically be about 50W/120mm fan unit on the CPU and 300W/120 on the GPU. Obviously the coolant in the GPU loop would heat up quite a bit and the coolant in the CPU loop would change minimally. In the past this was justified by a lack of any real consequence to your GPU running 40 vs 50 vs 60C. There were no buzzy onboard fans to make noise for that and you were still 20C+ cooler than those on air. On the other hand, the CPU overclocking crowd were pushing the limit. I ran a Titan X Pascal on a 120mm hybrid and it was relatively effective. Worst temps ever were about 54C on a very hot Summer day. However, the arrival of Turing (and presumably Ampere is the same) has changed this somewhat. For those interested in the highest possible GPU clocks, you must keep the temperature down. My 2080 Ti and most everyone else's will start to downclock at specific temperature markers starting not much past 40C. Now whether or not your performance is really suffering by going from 2100 to 2025 MHz is another question, but it is fairly clear. As a result, the manufacturers were forced off the 120mm 'stick in the back exhaust' model and now use larger radiators. While the new AMD versions appear to be more power efficient and less total TDP, I still wouldn't want one on a single 120mm. The air cooling has become more aggressive and you likely would see similar GPU temperatures between a triple fan and a 120mm hybrid. The hybrid might make up for it by being less noisy and the ability to direct a large portion of the waste heat were you want it to go -- in theory. Be aware hybrid GPU models almost always only cool part of the card on the loop. The VRAM or capacitors may be air cooled. I did see one proposed hybrid for 3090 that cools both on the liquid side. What that means in the GPU is still something of heat source inside the case, but not nearly to the same degree as air cooled.

 

Which brings it back around to what you are actually going to do. For the 500R listed in your specs, I think you would need to do a reverse flow with top/front exhaust and the GPU hybrid model exhausting from the front. Whatever radiator size that fits (240/280?). The AIO tubes won't be long enough for the CPU to make it to the front as intake and the top as GPU exhaust. You likely would want the same configuration for a custom loop with one flow stream. It may not be the most friendly water cooling case ever and if you are talking about spending this much, you may also want to consider case options to match whatever you decide to do.

Edited by c-attack
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Ah I didn't even realize the system specs are still posted. I am probably not going to overclock much I have done it in the past and generally don't care for the headache that much. As far as what the build I am thinking of. It will be a Phanteks P500A case with a 420mm Radiator on the CPU mounted in the front an AMD 5900x and either and AMD or Nvidia GPU around the 3080 class, would probably wait for the 3080ti or look more at the AMD gpu. Currently Running a 980TI That case could fit a 280mm Radiator in the roof and a 140mm fan on the back. I prefer the 140mm Fans as they tend to really cut down on noise. I was thinking of running both Radiators as intake and running the rear 140mm as the only exhaust. I am interested in keeping noise down for sure and like the clean look of a water cooled system. I also think it would be kind of fun to get into the water cooling a little bit.
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Overclocking won't change the GPU wattage much. You will have a high load whether at stock clocks or not. It can make quite a difference on CPU load wattage. Either way 420mm is more than enough for any CPU in 1:1. 420+280 in a combined loop should handle just about anything. Dual Intake vs Dual Exhaust is something you can decide for yourself later. Heavy intake biased radiators always benchmark well in the short run. However, the longer you run the more you add heat into the case. Besides the effect on RAM and other motherboard components, eventually you will heat up the radiators too if you can't remove it. Still this is what most people will do.
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Overclocking won't change the GPU wattage much. You will have a high load whether at stock clocks or not. It can make quite a difference on CPU load wattage. Either way 420mm is more than enough for any CPU in 1:1. 420+280 in a combined loop should handle just about anything. Dual Intake vs Dual Exhaust is something you can decide for yourself later. Heavy intake biased radiators always benchmark well in the short run. However, the longer you run the more you add heat into the case. Besides the effect on RAM and other motherboard components, eventually you will heat up the radiators too if you can't remove it. Still this is what most people will do.

 

Thanks all of your info was very helpful and really helped me to understand all this quite a bit better.

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So I have been looking into this a little more and am considering building a custom loop as I don't believe it would be that difficult. I am looking at installing a 280mm radiator up top and a 420mm radiator on the front of the case as I prefer the low sound of 140mm fans over 120mm fans. I'm debating between the XD3 or XD5 pump/reservoir. If I got the XD3 I could always mount it on the rear 140mm exhaust. The XD5 would need to be mounted on the front of the case behind the 420mm radiator. The Question I had about this is, I was thinking of including the Valved fitting at some point in the loop to make it easy to drain. I'm not sure the best point to put it. Maybe put the 420mm Radiator with the barbs in the bottom of the case and put the valved fitting on the output of that so it is always at the lowest point?

 

Also I would plan to integrate this into a graphics card once some models with integrated water blocks come out.

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having the barbs down will make it easy to empty one half of the radiator.. but it will also be a pain to bleed as air will tend to stay trapped in the end tank on top.

But the case may decide for you as some combinations are very hard or impossible, like having radiator fittings on top.. interfering with the top radiator.

 

With the barbs at the bottom and the XD5 roughly in the middle, when you'll drain, one half of the radiator will empty, and the rest will stay full. you will have to tip the case to work the water out. Remember to buy some extra fittings to make a draining tube.. just a piece of soft tubing you can screw at the end of the ball valve to drain into a bottle while you tip the case. Saves you from needing 4 hands.

I don't know if Corsair sells 420mm cross flow rads but that would make draining a breeze if it fits (the end tanks are slightly longer to accomodate fittings on both ends)

 

That said, with such rads, and possibly long tube runs, i wouldn't use the XD3. The "reservoir" is ridiculously small, it will be a pain to fill up ^^'

The XD5 is also little but getting the loop filled will be a lot faster.

 

Now for videocards with integrated waterblocks, they are rare. I know Asus are launching some with EK, maybe gygabyte too..

It's fairly easy to install a waterblock on a GPU, though i understand it's a bit.. stressful, taking apart the most expensive piece of kit of the whole build :)

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Putting together a complete cooling loop that drains down to the last drop on your first attempt would be a miracle beyond words. It's usually not possible because of compromises necessitated by the case layout and components. Lowest point and away from expensive hardware is about the best you can do. If you have to do a full drain it's always going to be moderately tedious, but this is only something you might need to do once or twice a year. I think lower front radiator is fine and meets the two core requirements.

 

The cool thing about the XD3 is it can be mounted to a fan or panel with a more integrated appearance than the classic pump + reservoir stack. It's actually fairly easy to fill and has a top fill port. It is also larger than you might think, which means mounting it to the rear fan may not turn out as expected. It's more like mounting a thick 120mm radiator back there. I thought that was what I was going to do, but in that position it makes the pump to CPU block run extremely short. As it turned out, putting it in the side wall toward the front was a much better placement and also created a "dual CPU block" look with the XD3 and XC7 synchronized.

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Thanks that is good to know about the XD3 and the size along with the filling issues. Thinking of putting a Y adapter on the bottom radiator with a valve that will be hidden so it will be easy to drain when I need to. I think I will have the room for the XD5 so I may go that direction since there is no difference in cost really. I am half tempted to mount a 420mm rad up front 280mm on the roof and 140mm radiator on the back. I believe I would have the room and I sketched out running the tubes(soft tubing). Maybe a bit of overkill but the cost didn't really seem to increase much adding that extra Rad. Go big or go home I guess, lots of overkill but should allow me to run the fans fairly low to keep noise to a minimum.
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lots of overkill but should allow me to run the fans fairly low to keep noise to a minimum.

 

That's the point for most, going very silent.

And yea, whatever the brand, rads and fans aren't the most expensive items.

 

Just remember you're getting into a neverending.. hobby ^^

It never ends with loop order tests, trying various fittings, various placements and so on to get it the most efficient possible :)

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  • 2 weeks later...
Just another question. On the XD5 Pump/res combo it looks like I can plug in the pump PWN directly to the motherboard and control it that way if I wanted. What about the temperature sensor?, there is a plug on the motherboard for temperature sensors will it read that or will I have to buy the corsair units to see that. I don't really care about any of the lighting stuff so would prefer not to have to deal with ICUE.
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The XD5 gets its speed control commands from any PWM header. Motherboard headers will work. Actual pump power is along the molex connector back to the PSU.

 

Many motherboards do have a "T-sensor" or water sensor plug. It's the same as what's on the Commander Pro (2 pin 10K thermistor). If your board does not, then it likely makes more sense to set it to a fixed speed depending on the control options available.

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