Question Could fans affect CPU peformance?

Jan 21, 2021
Around 1 week ago built my first computer (i9 processor, 32gb ram, gtx 1660 super), the process was very confusing but eventually after 11 hours of reading the manuals/youtube videos - finally figured it out and the computer works fine. Installed Mint and been using it without any issue,

Without any issue until... I installed Virtualbox Windows (guest) on the Linux Mint (host).

The problem was that the Windows guest vm was laggy.
I have spent 2-3 days of researching and trying everything I could; installing different drivers, adding more processors/ram to the virtualbox settings, changing the virtualization mode, etc etc etc.
Nothing worked.
Strangely however, there were times rarely when the virtualbox was running SUPER SMOOTH (for like 2-5 minutes) and then it would go back to being choppy and laggy after restart.

It wasn't until now that I developped the theory that the only possible reason this could be happening is due to my beginner level in building computers. Specifically the CPU Fans.

My computer has 5 fans + liquid cooling system. 3 come in the case, 2 on top of the liquid cooling unit.
Following instructions (it is difficult when 3 different manual contradict each other)

I did the following:
  • Liquid cooing unit I plugged into the SATA cord
  • the 2 fans ontop of the liquid cooling (part of the liquid cooling system) I plugged into the [CPU FAN] socket on the motherboard.
  • the 3 individual fans that came with the case (Fractal Design) I plugged into the case's chip on the side of the case, and then plugged the cord from that chip into the [OPT_FAN] socket on the motherboard.
The reason:
  • I didn't plug the variable fan speed chip into [CHA_FAN] is because the cord doesn't reach there, so I thought it wasn't designated to go there.
  • I didn't plug the individual fans into the individual [CHA_FAN] sockets is because I read that that the back chip is designed to vary the speed of the fans based on temperature of the CPU/motherboard. I also read that this could be not be achieved with CHA_FAN if only 3 connections (instead of 4) are on the cable from the fan, which is the case for these 3 fans.
  • I didn't plug the chip into [CPU_FAN] main socket is because it is being used by the liquid cooling unit (specifically the cable comes from the 2 fans on the liquid cooling system).
Extra info:
All 5 fans work (I could see them spinning), however:
  1. They are VERY quiet. (Im starting to wonder if the variable speed even works)
  2. In BIOS screen they don't show up (it only shows 1 fan)
My theory about why VirtualBox is slow:
  1. CPU works normal when just Mint running
  2. When I run Virtualbox, the CPU starts to get hot - but is unable to either detect or control the other fans to spin faster, making it overheat slightly, which doesn't allow the processor to work efficiently
  3. and therefore goes back to being laggy to save the temperature

My question:
  1. Is this theory possible (limited CPU performance due to incorrect fan installation)?
  2. Should one be using the variable speed chip on the PC case for fans? If yes, which socket to plug in (cha_fan or opt_fan)?
  3. Is there some software (for Linux) to boost the CPU performance temporarly to listen if the other fans will increase in speed?

Sorry for the super long intro.
Been stuck on this problem for 3 days.

Would really appreciate any advice.

Thank you.


Oct 11, 2015
  1. The chassis fans will more than likely not make a major throttling issue like you believe to be experiencing. However an improperly installed CPU cooler can. Just to confirm the basics thermal paste was used while installing the cooler? What is the cooler? (Different coolers wire differently.) From what you are describing my guess is a cooler pump not running at high enough RPM or improper thermal paste application.
  2. All fan headers are variable speed. 3 pins are voltage control, while 4 pins are PWM. The fans you have determine the setup. cha_fan headers are for chassis fans and opt_fan is used for optional fans which are pretty much a multi roll header. Regardless on most good boards you can setup custom profiles that will let you configure either header to fill the need of whatever you need the fan to do. The chip you are describing is probably a hub, and yes it is fine to use as long as the input is good.
  3. Any benchmarking tool will warm things up, but you shouldn't need it. If you are having issues as bad as you are describing you should be able to see what is going on in bios.
Jan 21, 2021
> jasonf2
Thank you for the detailed answer.

I just connected all the individual fans into individual cha_fan sockets.
They have showed up on the BIOS screen.
However, the result is still the same - virtualbox is still slow.

Very strange...