[SOLVED] Ryzen 5800x constantly hot and underperforming

Dec 11, 2021
I built my very first PC in February of 2021.

CPU: Ryzen 7 5800x
CPU cooler: MSI MAG 240G AIO
Mobo: Asus Prime x570
RAM: Gskill 16GB Ripjaws
GPU: Radeon XFX 6900xt Merc Speedster
PSU: Super Sunflower 850W 80 Plus Gold
HDD: 2x1TB Nvme drives

For the first time a few days ago, I decided to benchmark my CPU and found that I only got a score of around 10500 in Cinebench R32. I have seen that others online are getting over 15000 for the same CPU.

I noticed that the CPU utilization was not as high as I would expect it to be during the Cinebench run, but looking at the CPU temp in hwinfo I could see that the CPU was running at 90 degrees Celsius. I thought this may be why performance was being hampered - the CPU was getting too hot. During the test, CPU utilization in task manager showed only around 70% - 77%.

I then moved the radiator from being mounted to the top of the case with fans pushing air up and out of the case, to the front of the case with fans pushing air into the case. See the link below for picture I've taken (excuse the poor cable management). This move did not do much, if anything, for the CPU temps.

I then decided to purchase and apply some new thermal paste. Running Cinebench after that brought my score up to around 11900. Much better but still much lower than I was expecting. During this Cinebench run, CPU utilization showed around 90%.

What I find really strange is that the idle temps of the CPU are very high. Right now I've only just switched on my PC and the CPU temp is over 80 degrees Celsius while idling (!!!!). See Hwinfo screenshots below which shows the temps and speed at which the pump is working (I believe it's running flat-out), as well as CPU utilization in task manager. The CPU is currently idling in these screenshots.
Hwinfo 1
Hwinfo 2
Hwinfo 3
Task manager CPU utilization

I would really appreciate some advice on next steps to take, I really just want to get the performance that I paid for :(

Thank you in advance,
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I agree, the cooler is not doing it's job. I also had a AIO phase but went back to my Noctua tower cooler, my 5900x is 33-35c at idle and 68c running Cinebench at 23c ambient. Never gets over 72-75 gaming when the GPU is also adding heat to the overall sytem.
Dec 11, 2021


Apr 24, 2021
With no cooler your cpu would reach 100C in about a tenth of a second and automatically shut itself down.

It is probably not mounted properly or maybe the pump isn’t working. Whichever it is, that’s a really bad cooler and needs to be replaced.

if you want the stench of MSI to still be infecting your PC even after you remove it, then sure no harm in keeping the fans.
@TommyTwoTone66 I love your sense of humour.

Ok, I'll replace the cooler and give an update here in the next few days.

Those MSI AIO's have the pump in the radiator. I can see why they're not the best especially if mounted in the top of your case. But unless it's a semi-dead one it should do you well enough. The radiator just has to be mounted in front, side or bottom and never the top.

5800X's are toasty hot CPU's if not properly set up. It's even EXPECTED and BY DESIGN for them to reach for 90C. But there is a lot you can do to help using the new PBO2 and undervolting with Curve Optimizer. It's not that hard, just look on YouTube for some how-to's.

With PBO2 and CO my 5800X never gets out of 70's unless testing with Prime95, even then it's only in the low 80's. That's even though it hits 4900Mhz in light loads. I can even set it up to hit 5050Mhz in light loads, but that hurts heavy loaded benchmarks like Cinebench. A setup like that would probably work better for gaming, if I did the e-Sports variety where it helps.
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