iCUE H115i RGB PRO XT Liquid CPU Cooler

So I just recently purchased a new AIO cooler the H115i Pro XT. How ever I noticed I can only get the fans to spin up to 1800 RPM. When I checked the specs on the website for the product it states they can spool up to 2000 RPM. Is anyone else having this issue? I have the AIO hooked up to a Corsair Commander PRO. I even tried to hook the USB into both ports on the Commander and have the same results. I also forced updated the firmware as well. How ever I am still having the same issue. Anyone help would be appreciated. Thank You

It is likely physical (pressure) and not mechanical or software related. The "2000 rpm" is the rated speed in free air with no resistance, +-10%. Even disregarding normal variance, you typically cannot get the same maximum speed out of any fans once you put some resistance in their way, whether radiator, dust filter, or heavy case mesh. Glass is a substantial barrier, so if you have it mounted behind the front fans, sucking air through the side venting would be enough to do this on its own. Top mount exhaust, the glass will also add clear resistance.

 

I would say this is the expected result for a 680x and you don't really want to be running 1800 rpm anyway. It's going to be mostly noise in exchange for 1C at that level.

I understand what you are saying that it could be physical pressure. How ever I was running a Hydro Series™ H100i RGB PLATINUM 240mm Liquid CPU Cooler in the same case mounted in the exact same spot before I upgraded to the XT. I was able to spool the fans spin to max RPM if I wanted. Regardless of were the AIO is mounted I should be able to spin the fans at max RPM. I just don't understand why resistance would have anything to do with what speed you can run the fans. The AIO is pushing air out the top of the case. Are you saying the pressure from the glass is keeping the fans from running max RMP? How ever this cooler is an absolute beast even at 1500 RPM's for CPU temps. Edited July 3, 2020 by Omenoflight

I just don't understand why resistance would have anything to do with what speed you can run the fans. The AIO is pushing air out the top of the case. Are you saying the pressure from the glass is keeping the fans from running max RMP?

 

The same reason you can run faster in still air than into a 25 mph headwind or with me grabbing onto the back of your shirt. Resistance is resistance, regardless of the direction it comes from (front or back of fan). At 12v 100% maximum, the motor produces X watts of power. That’s all there is and the “2000 rpm speed” is for ideal conditions. Everything else in world will slow it down.

 

Your old SP120L fans could have been over-performers on the +10% instead of the minus, but also as a general rule the larger the fan, the more likely you are to see it affected by resistance. There are several factors in that, but as a long time 140mm radiator fan user, I can’t remember a single one that ran its box spec speed on a standard 30mm radiator. That is at least 100 different fans across a multitude of brands and that is with a fairly open test case.

 

However, the good news is fan speed is not that critical to end performance. You don’t drop 1-2C because you add 50-100 rpm. Furthermore, it is really hard to make gains at the higher speeds except on very dense FPI radiators that offer a performance penalty at low speeds in exchange for better results at extreme levels. Those are better saved for benchmark or heavy-duty uses. The radiator on all Corsair coolers will be a medium FPI density that offers good performance on both ends. 1500 is the most you’ll ever need and I typically tested at 1200-1300 for high watt CPUs without any meaningful penalty.

Thanks for your help and all the information. 1500 RPM is enough to keep everything pretty cool. I was just surprised I could not push the fans to max like with the older cooler lol.