Jump to content
Corsair Community

Liquid Cooler FAQ

Recommended Posts

Before posting with cooler issues, especially questions about CPU temperature, please include the following information in your post:

  • What CPU and is it overclocked?
  • What is the max vCore (in Link/iCue, this is "vCPU")?
  • What is the coolant temperature?
  • How quickly does the coolant ramp up and how quickly does it cool down?
  • What is the ambient temperature?
  • Is the cooler intake or exhaust?
  • What GPU are you using? (Hint: Fill out your system details fully.)
  • How are you testing temperatures?

And please take a look through this FAQ ...

A. General Cooler FAQ:

This post has answers to common questions about coolers that we've seen here on the forum. Do you have additional questions? Feel free to start a new thread!

A1. My cooler used to show up in Link/iCue but suddenly it’s gone! What happened?

Go to Windows Device Manager. Expand “Universal Serial Bus controllers” and look for “Corsair USBXp Driver”. If it’s disabled, enable it. If it’s enabled, disable it and then re-enabled it. This resolves the issue the vast majority of the time.

Also, if you are running EVGA Precision XOC, disable the RGB sync feature or - better yet - just make sure that you are on the current version. We’ve had several reports from users that are using this particular tool that it conflicts with Link (badly) and attempts to take over control of the cooler’s RGB features, blocking Link from accessing the cooler and possibly causing driver issues. Note that this is only true of older versions; current versions of XOC have fixed this.

Note that other monitoring tools that connect to the Corsair coolers can also cause issues. In most cases, it is possible to disable them from monitoring your Corsair cooler or to shut down iCUE if you need to do monitoring with other tools. HWInfo is a common culprit and it can be disabled in the Safety section of the settings. Just uncheck "CorsairLink and Asetek Support"

Finally, check in your BIOS and make sure that both "Legacy USB Support" and "XHCI Handoff" are enabled. We've seen several users where this has resolved issues with device detection.


A2. I have a custom fan curve but I don’t want to/can’t run Link/iCue all time. Can I have my custom fan curve or desired settings while Link isn’t running?

Yes, with most of the Link/iCUE capable coolers, you can do this.

For Link: Adjust your desired settings in Link and then go to “Options” … “Devices”. In the dialog, look for your cooler. If it has a hyperlink under it to “Use current settings as default”, click it and your current, custom settings will be written to the cooler. This includes fan curves, pump speed and LED color.

For iCue: Set your Performance settings for the Pump. Click the hamburger menu next to "Profiles" and click the icon that looks like an SD-card. It will be labelled "Save Static Lighting and Performance to the Device".


A3. What temperature should be used to control the fan speeds?

The temperature from your cooler is the ideal temperature to control the speed of your fans. With liquid coolers, the CPU is cooled by the liquid (via the cold plate). The fans blow cool air through the radiator in order to cool the liquid coolant, not the CPU. As the liquid coolant has a higher heat capacity than air or the materials used for your CPU, it will both warm up and cool down more slowly. This will keep your fans at a reasonable speed and prevent spikes in the fan speed as well. Finally, the default fan curves include with Link are designed to work best with the cooler as the temperature source.

If you do not have your fans connected to the cooler's fan controller, CPU temperature can also be used. This, however, is subject to a greater deal of variation and isn't always directly indicative of coolant temperature. If you are using a Commander Pro or your motherboard has a connection for an external temperature sensor, you can place it in the exhaust of your cooler and use that to control your fan speed as this would be directly related to the coolant temperature.


A4. Should I connect the fans to the cooler, the motherboard or a Commander Pro?

Ideally, you should have the fans connected to the cooler itself. The cooler has a integrated fan controller that will control the fans based on the coolant temperature, even if Link or iCue isn't running. As discussed above, the coolant is the best and most appropriate temperature to use for fan control.

If you have a Commander Pro, you can create a fan curve based on the cooler temperature. However this fan curve will require software (Link or iCue) to run; when this software is not active, the fans will run at 100%. Again, as mentioned above, an alternative is to have one of the Commander Pro's thermistors in the exhaust air flow. On my system, the radiator exhaust is pretty reliably 0.5C above the reported H115i PRO's temperature.

If you connect your cooler's fans to the motherboard, you only have the CPU temperature to use as a basis for fan speed control. As mentioned above, this is not ideal for a number of reasons.


A5. I want to replace the stock fans. What fans should I use?

You can use any 4-pin PWM fan. DC-controlled (3-pin) fans cannot be controlled from the Corsair AIO liquid coolers and will run at full speed all the time when plugged in to the cooler’s fan headers. The ML fans are highly recommended for radiator use but the HD and LL series of fans will also work well (with a little more noise and higher fan speeds) and they look fantastic in a push/pull configuration.


A6. I want to replace my stock fans with ML-RGB fans but they don’t perform as well as the original ML-PRO series of fans. What’s up with that?

The ML-RGB fans will do an excellent job cooling your radiator. Over a certain fan speed, there are diminishing returns when it comes to fan/radiator cooling performance. The performance spec difference between the ML-RGB fans and the ML-PRO fans is due solely to the higher RPM supported by the ML-PRO fans. That said, when using ML-PRO fans on an H100i V2, I’ve limited them to the same maximum speed as the ML-RGB fans (1600 RPM) and noticed little performance difference (a little less than 1C in coolant temperature) with significantly less noise.


A7. My pump is powered by a SATA power connection. Do you need to plug in the fan header?

If your pump is powered by a SATA power connection, the pump does not need to be plugged into a fan header for proper operation. The fan header connection on your pump is there to provide a tach signal to the CPU_FAN header so that you don't get a CPU fan warning on boot. Because of this, this should only be plugged in to the CPU_FAN header. This includes the new PRO series coolers as well as some of the previous generation coolers.


A8. Should I use push or pull for my fan configuration?

It doesn’t matter. Either will work equally well; there is no difference. One thing to consider, however: if your fans are configured as pull, it’s easier to clean the radiator of any built-up dust.


A9. What about push/pull?

Push/pull can give you good cooling at lower fan speeds, resulting in a quieter system but only if both fans are balanced. If they are not, it’s possible that they could interfere with each other. And, in most cases, it's not necessary.


A10. Can I power all of the fans from the cooler in a push/pull scenario using splitters?

It depends. If your cooler is powered from the fan header, no. You do not have enough current to adequately power more than 2 fans. If your cooler is SATA powered, you may be able to. You will have a 2A limit on the current used by the pump and the fans. Of those 2 amps, the cooler will need up to 450mA (0.45A). So if your push/pull set up is less then 1.55A, you should be good to go.


A11. I have my cooler plugged into the CPU_FAN header and I’m seeing some really crazy fan speed readings for CPU_FAN. What’s up with that?

Most Corsair coolers report RPMs to the CPU_FAN header equal to approximately ½ of the fan speed. This prevents a CPU Fan warning from your BIOS when booting but and can give you an approximate speed of your pump if you aren’t running Link but otherwise it’s nothing to be concerned about. Note that the new Pro series coolers (H150i Pro and H115i Pro) report actual pump speed on the CPU_FAN header.


A12. My temperature is too high! What’s going on?

This is a tough one as there could be a number of issues. First, keep in mind that occasional spikes into the 70’s or low 80’s is not uncommon, especially with a stock Intel processor running a stress test. This is primarily due to the poor quality thermal interface material (TIM) that Intel uses in current processors.

Second, take a look at the voltage that your CPU is using (vCore). In Link and iCue, this is listed as VCPU. Other monitoring tools may list it as VCore or something similar. A stock Intel CPU will have a vCore of 1.2V. Various motherboard manufacturers have default settings on their motherboards that, by default, overclock processors with auto voltage settings, even if you didn’t set any overclocking settings yourself. (For example, Asus Multi-Core Enhancements is on by default and is technically an overclock). Higher voltages will lead to higher temperatures. We’ve seen several reports from users that have seen voltages greater than 1.4V using the default settings on their motherboard. Such voltage will definitely cause heat issues and may shorten the life of your processor.

Poor mounting can also cause increased temperatures. Take some time to examine your mounting and make sure that the cooler is tight against the processor. Also check the standoffs and make sure that they are fully screwed into the baseplate. Note that the baseplate may be loose against the back of the motherboard when the cooler isn’t mounted; this is fine as long as it is tight once the cooler is mounted on the CPU.

From there, other issues may be environmental, particularly if you see both your CPU temperatures and your coolant temperatures increasing significantly while gaming. This may be due to the thermal environment in your case, particularly if your cooler is set as exhaust. GPUs, while under load, generate a lot of heat. If this heat isn’t properly managed, it can cause systems to heat up significantly. If the air that is going through the radiator is warm, the coolant won’t be able to get cool. If the air blowing through the radiator is warmer than the coolant, it will actually increase your temperatures. In this case, you need to examine your airflow to ensure a steady supply of cool air to your radiator. We've had several users with heat issues directly related to poor airflow.

Finally, there is always the possibility of a pump failure.


A13. How do I know if my pump failed?

There are a couple of key indications of pump failure. However, if you have a cooler that is powered from the 3-pin CPU fan header, make sure to review the section regarding powering the header before assuming that you have a failed pump. Improperly powered pump will often “appear” to be failed when, in fact, they simply aren’t getting enough power.

  1. The CPU temperature immediately increases to 90+C, even while in the BIOS.
  2. The pump head feels warm while the hoses going to the radiator are cool. Or one hose is significantly and noticeable warmer than the other one.
  3. The CPU Fan RPM reads 0 when the 3-pin header is plugged in to the CPU_FAN connector.


A14. What do I do if my pump has failed?

Go to the Support Ticket System and open up an support ticket to begin the process of an RMA. Make sure that you have a copy of your original receipt; this is required for any RMA. Corsair Support may suggest some troubleshooting steps to attempt to help you get up and running. Do not attempt to repair the cooler yourself or take it apart; this will immediately void your warranty.


A15. I just got one of those new cool PRO series coolers (H100i PRO/H115i PRO/H150i PRO) and I went to update the firmware ... and then it said it failed to load the firmware update. Help!

This is not an error. This is just a message that is displayed when no firmware was found for the cooler at all. The firmware that this cooler ships with is the most recent and updated firmware. The message really should read: "No firmware was found for your device." Note that this is also true for the Vengeance PRO RGB RAM.


A16. I'm installing my cooler and I'm concerned about the amount of play/wiggle between the backplate and the motherboard. Is this a cause for concern?

No, this is completely normal; there will be some amount of play between the backplate and the cooler. As you tighten the cooler down, this will go away. If there is play afterwards, then it's possible that you installed the wrong standoffs. Do not, as some have suggested, add additional washers or spacers to the backplate!


A17. What's the best fan curve for my AIO cooler?

While the built-in, default curves certainly work, they are often less than ideal and aren't always optimized for your environment. A custom fan curve, based on your environmental conditions (room/ambient and case temperature are the dominant factors) and system, works best for most users and allows you to balance cooling performance with noise. To create your custom curve:

  • Boot up your computer and let it sit idle on the desktop or doing light work for 10-15 minutes. This is your baseline coolant temperature. You should set a fan speed that is quiet and non-intrusive for that temperature. For most people that is probably between 800-1000 rpm on a 120mm fan, but it is your choice. At idle, an extra +2C is irrelevant.
  • Leave yourself some ambient temp wiggle room and start a slow climb about 3C further down the line. You don't want the fans to kick up because it is +1C warmer in your room today. You can expand this as needed. This also can be a bit tricky if you have one of those rooms that is cool 18C in the morning, but 27C in the afternoon. For that, you may need a "AM" and "PM" curve.
  • Boost the fan speed up to a tolerable level around the +6C mark. This is generally where most people top out for CPU max loads and general multipurpose loads. If you have a lot of GPU heat in a small case, you are likely to see higher numbers when under GPU load and should adjust accordingly. Regardless, find the maximum coolant temperature you normally see during real use and set the fans to the highest level you are willing to endure.
  • Set a max RPM blast about +5-7C further down from the highest temp you have seen. This serves as a warning system in case things are out of balance. You will most certainly hear the fans before you notice the coolant temp is abnormally high.

Shamelessly stolen from @c-attack.

A18. What's the relationship between the coolant temperature and the CPU temperature?

The relationship between coolant temperature and CPU temps is this:

  • Coolant temperature is the minimum possible CPU temperature when the Vcore is at 0.0 volts. You won't ever be at 0 volts except when shutdown, so in practical terms you will always see idle CPU temps just a bit above the coolant temp even when using C-states, EIST, and other power saving features. Turn all those off and the difference will increase.
  • +1C coolant temp = +1C CPU temp. Every time you add 1C to the coolant temperature, you raise that basis/lowest possible CPU temp by 1C as well. A typical 100% CPU load for the 8700K is going to be +4-6C, depending on CPU settings. That is not a lot in comparison to the voltage part of the the total CPU temp (typically +30-50C). Fans help reduce coolant temperature, not the +30C from the voltage. So even with maximum fan speed, you likely can only reduce your CPU temp by a few degrees. While this seems detrimental, it is not. An air tower is bound by the same rules, but has a much smaller capacity to hold heat. It will suffer a greater penalty when faced with the same load. In your case, the "penalty" is the coolant temperature rise and that is small.
  • Typically most people see coolant temp rises of +4-6C for CPU only loads or general mixed use. Gaming or other max GPU loads often give the appearance of more. Some people will see as much as +10C while gaming with large watt GPUs, although it has nothing to do with CPU load or efficiency. When you heat up the case with the GPU waste heat, you raise the local environment temperature. Only 3-4C of the gaming temp might be from load. The rest is because you raise the case temp by +6C and that's the final rule....
  • Minimum coolant temperature is case ambient temp in that specific location. Not surprising, you can't make the liquid in the cooler colder than the room or case temp. Most people will see coolant temps of +4-7C above their room temp and pretty much exactly what the local case temp is at the radiator mount location. Some place are worse than others.

Shamelessly stolen from @c-attack ... again


B. Fan Header Powered Coolers FAQ:

This section is specific to those Corsair coolers that are powered by the fan header using a 3-pin connector. This includes the following coolers:

  • H100i V2
  • H105
  • H90
  • H80i V2
  • H75
  • H55

This does not include the Pro, Platinum, or Elite series coolers. If your cooler has a USB power connection, you can skip this section completely!

B1. My motherboard has an AIO_PUMP fan header. Can I use that?

You may but you’ll need to disable the CPU Fan speed warning in your BIOS. The AIO_PUMP headers are standard fan headers that are set, by default to 100%/12V mode. Because of this, they do work well for these coolers. However, using the CPU_FAN header will give you a warning in the event of a total pump failure so this is the recommended installation option.


B2. My AIO isn’t working correctly

First, check that the pump is powered correctly. These coolers get all of their power from the fan header and require a full 12V at all times. (See http://forum.corsair.com/v3/showthread.php?t=168801). In most cases, the default motherboard settings will attempt to control the speed of the pump as though it were a fan based on CPU temperature … and as a 3-pin, DC-controlled fan. This will reduce the voltage supplied to your cooler during idle periods, resulting in a malfunctioning cooler and possible long-term damage resulting in early pump failure. How you set this header to full speed varies widely by motherboard manufacturer so consult your motherboard manual for the best way to do this. You may ask on the forum about specific manufacturers and if a user has that motherboard or is familiar with that manufacturer’s BIOS, they may be able to give you specific guidance on how to do this but it is not guaranteed.

Some symptoms that indicate that your cooler is not being powered correctly:

  • The cooler is not recognized by Link
  • Fan speeds are 0 RPM even though the fans are plugged into the cooler
  • Pump speeds are low. In “Quiet” mode, the pump speed should be around 1900 RPM. In “Performance” mode, this will be around 2900 RPM.
  • Pump speeds vary with CPU temperature. The CPU_FAN header defaults to using CPU temperature for fan speed control. This will actually increase/decrease the voltage supplied to the pump based on the CPU temperature, resulting in variable pump speeds. When powered correctly, the pump speeds do not vary significantly.
  • Cooler LED does not turn on


B3. But if I set my CPU_FAN header to 100%, the fans are going to be LOUD!

No, they won't. The CPU_FAN header setting doesn't control the fan speed. The fan speed is controlled by a fan controller that's built into the pump. If you don't set the fan header to 100%, the pump won't get the full voltage that it requires to operate properly. In that case, it's very likely that the fans will be quiet ... because they won't have enough power to spin at all! So please, set that fan header to 100% power and then you can control the fan speeds through Link.



Questions about RGB and how to get your bling on? Check out the Corsair RGB FAQ and Sample Diagrams.

Have other questions? Feel free to start a thread and ask! That’s why the forum is here. Please refrain from commenting on this thread. If you have suggestions for addition to or revision of this post, please send a PM to DevBiker.

Link to comment
Share on other sites

  • 1 month later...


This topic is now archived and is closed to further replies.

  • Create New...