Need help for setting Gigabyte B450I and H80iV2

I bought Gigabyte B450 I AORUS PRO WIFI ITX and Corsair H80i V2.

H80i v2's manual states:

plug pump-3pin to CPU_FAN header,

plug both 4pin fans to Y splitter coming out of the pump,

plug USB to MB USB header.

I followed the above instruction. I only installed one fan due to space constraint in ITX case.

Corsair forum says " The fan connector supplies power to the H80i V2 and does need the full 12V at all times. Setting it to PWM mode or setting it to 100%/Full Power/Speed Control Disabled (the terminology varies by mobo manufacturer). "

Ref: https://forum.corsair.com/v2/showthread.php?t=178032&t=178032

When I set BIOS CPU_FAN control mode to "Auto", the fan curve in BIOS seems to work. But my pump speed seems to be too low (fan 750rpm, pump 1500rpm at idle in HWinfo) by Corsair standard. I guess Auto is voltage mode in my case. I verified this by using voltage mode and the voltage mode behave the same.

In this mode (AUTO in BIOS), with my fan curve (starting 35% at 35C, 50% at 55C, ...), when I run Cinebench R20 mutil-thread, fan 1400rpm, pump 2400rpm, CPU 75 degree C, liquid 39.5 C. Seems normal. CPU is a bit high compare online results (usually people report 70C for 3600x at full load)

If I set BIOS CPU_FAN control mode to PWM (There is no full speed option in BIOS). The pump seems to work properly at high rpm at idle (~1900rpm), but radiator fan runs at very loud high rpm like full speed. Also, the fan curve in BIOS no longer have effect (normal, silent, manual curve all the same.)

Please help. Thanks!

Do not run it on Auto. It will damage your pump. The behavior that you are seeing is due to reduced voltage to the pump. That's not good; the pump is not designed for reduced voltage.

To control the fans with the H80iV2, you'll use iCUE or Link. This will allow you to set the fan curves appropriately. Note that HWInfo does cause conflicts with iCUE/Link; you'll need to disable Corsair Link/Asetek Support in the Safety tab of the configuration.

Do not run it on Auto. It will damage your pump. The behavior that you are seeing is due to reduced voltage to the pump. That's not good; the pump is not designed for reduced voltage.

 

To control the fans with the H80iV2, you'll use iCUE or Link. This will allow you to set the fan curves appropriately. Note that HWInfo does cause conflicts with iCUE/Link; you'll need to disable Corsair Link/Asetek Support in the Safety tab of the configuration.

OK. I set the CPU_FAN control to PWM in Gigabyte BIOS. There are only three options: Auto, PWM, Voltage.

I installed Corsair Link, but I don't want Corsair Link to run at the background. Nor do I want 100% fan speed.

What could I do?

Thanks!

With Link, you can set the fan curve and then save to the device. I can't recall where exactly that is in Link but it does let you do that.

The fan curve will be based on the coolant temperature by default - that's the correct method.

With Link, you can set the fan curve and then save to the device. I can't recall where exactly that is in Link but it does let you do that.

The fan curve will be based on the coolant temperature by default - that's the correct method.

I tried using coolant temperature to set fan curve, it works after exiting LINK.

But CPU can go to 80+C and fan speed won't ramp up since coolant is still cool.

If I set fan curve based on CPU (Tctl/Tdie) in LINK, the fan curve won't work after exit LINK.

With LINK in the background, my Cinebench score drop from 3712 to 3665.

Still not a optimal solution.

Can I plug a radiator fan to motherboard SYS_FAN header and use its PWM to control fan speed?

You can ... but it won't do much good.

The fans on the radiator don't directly cool the CPU, they cool the coolant. Which is why the preferred (and optimal) solution is to have the fans controlled by the coolant temperature.

That said, you will have challenges using a single fan on the H80 radiator. That radiator is super thick - so the push/pull effect of the two fans is better. You may want to create a custom curve to ramp the fan speeds up sooner in order to create the additional airflow and pressure. What coolant temps are you seeing, btw?

You can ... but it won't do much good.

The fans on the radiator don't directly cool the CPU, they cool the coolant. Which is why the preferred (and optimal) solution is to have the fans controlled by the coolant temperature.

 

That said, you will have challenges using a single fan on the H80 radiator. That radiator is super thick - so the push/pull effect of the two fans is better. You may want to create a custom curve to ramp the fan speeds up sooner in order to create the additional airflow and pressure. What coolant temps are you seeing, btw?

ambient temperature 22C. pump speed high ("performance")

1. fixed 40% speed

two runs of cinebench R20, coolant starts about 36C, and rises to 39C (CPU 73C)

2. custom fan curve based on coolant tempature.

two runs of cinebench R20, coolant starts about 36C, and rises to 39C (CPU 80C)

Prime95 about 3-4 mins, coolant starts about 35C, and rises to 41C (CPU 81C)

I don't think it is mainly due to one fan configuration.

Naturally, CPU temp will rise rapidly under load, while coolant temp takes a long time to build up 1C rise. No matter how steep the curve is, fan speed still won't ramp up much for sub-1C change in coolant but CPU is already at 80C. But fan speed can respond to rapid changing CPU temp. This effect will be more obvious when PC has been idling for a while and coolant has full cool off (34C) and a full work load cause CPU to go 80C while fan is still at low speed. Then CPU throttles.

Ryzen 3000 CPU are known to boost differently under different temperature.

At fan full speed, my 3600x is under 72C and can boost to 4.08GHz all core in Cinebench R20. but at 80C, it will only boost to 3.99GHz.

I don't know this dilemma exist in newer models like H60(2018).