Recently I’ve been running hashcat for some proof of concept WPA cracking with the below specs:

• CPU: i7 4790k (mild overclock @ 4.5GHz)
• GPU: 1 x Powercolor RX580 Red Devil ,1 x NVIDIA GeForce GTX 660
• Motherboard: MSI Z97-G43
• Case: Cooler Master 370 Elite
• Cooling: Air: 1 x 140mm fan intake (front), 1 x 140mm fan intake (side), 1 x 120mm exhaust fan (top rear)

With this set up it would run about 245KH/s but I after some time (minutes to hours) it would hard power off with similar symptoms to a dying or overheating PSU, only I wasn’t convinced. I’ve long fancied upgrading to an all in one CPU liquid cooler but I don’t fancy messing around with a DIY version – I’m sure this gives the optimum cooling result, and a the engineer in me loves to build, fiddle, and optimise things, but I just wanted a drop in solution, so I opted for the Corsair H100i Pro as it was readily available is probably one of the best 240mm coolers (2 x 120mm fans).

I was a bit limited by the case design – it won’t allow to front mount without some modification to the drive bays (maybe another day), there are 2 x 140mm side vents, but the depth of the radiator and fans won’t fit against the graphics cards, and I didn’t fancy mounting the fans outside the case to suck in the dirt. So it will be mounted on the top of the case using the two fan cut outs as exhaust ports. I will also reverse the exhaust fan at the back to pull in cooler air.

Before with just the fans, I could feel a definite hot spot around the (unused) 5 1/4″ drive bays – this is right where the Arctic air cooler would pull the air in from

Results

Tested using Hashcat with the -w 4 setting (nightmare mode) and recording results via Open Hardware Monitor and set to log to a file.

Ambient temperature ~ 21C

Hashcat was left to run for ~1 hour after allowing computer to cool all night long, all CPU/system fans were running at 100%

Cooler	Main Board Temp	CPU Core Temp	RX580 Core Temp	GTX 600 Core Temp
Arctic Xtreme	41	89	84	65
Corsair H100i Pro (1)	40	76	79	61
Corsair H100i Pro (2)	43	79	83	63

(1) – With the rear fan acting as an exhaust fan – sucking the air from just above the GPUs, but potentially not providing cool air for the CPU fans

(2) – With the rear fan acting as an intake, providing cooler air for the CPU fans

New cooler:

Outgoing cooler: