I Ran My 12 Core CPU With NO Thermal Paste (Here’s What Happened!)

I recently had the crazy idea to REMOVE all my CPU’s thermal paste, and run a number of stress tests on it. There was a problem here though (aside from the obvious): my CPU isn’t some super low power 2 core chip. It’s actually an expensive 12 core Ryzen CPU.

So this video looks at exactly what happened when I ran my 24 thread AMD Ryzen 5900X CPU without any TIM, and also when I tried doing 4K gaming and video editing on it. I also discuss whether the motherboard safety measures helped me at all, or whether my CPU sustained any sort of damage.

Finally I compare my 90 degree celcius temperatures to the “normal” PC temps, which are closer to 40 degrees at idle.

If you prefer text over video, please read on for the guide/transcript version of this video.

Video Transcript And Guide

Showing three of my new black Arctic fans inside my case
My Ryzen 5900X with no thermal paste

Hey everyone , I LOVE my 12 core Ryzen CPU. It cost me £450 and it handles everything from gaming to 4k video rendering with ease. But when I was working on another video, I had one of those “intrusive thoughts” – and the thought won. So I promptly REMOVED all the thermal paste from my beloved Ryzen, and booted back into Windows. The results weren’t pretty, so here’s EXACTLY what happens when you run your CPU with zero thermal paste.

So we all know that thermal paste is important because the surface of a CPU and also the heatsink will always have very tiny, microscopic bumps and pits in them. That’s a natural part of the manufacturing process, of course, but thermal paste helps “fix” these micro impurities and because TIM conducts heat, all the toasty temperatures from the CPU can be better passed to the CPU cooler and heatsink.

So if some crazy idiot decides to use isopropyl wipes to remove all the thermal paste, there’s no real “bridge” for all that heat to move from the CPU to the heatsink. It’s a bit like eating a sandwich without any mayo or filling. Yuk, needs more thermal paste. Yum!

Booting Up Into Windows

HwInfo temps when I first booted up
HwInfo temps when I first booted up

So what exactly DOES happen? Well when I first booted up, my computer sounded like it was about to take off – because all the fans were running at 100% speeds. They were completely maxed out. I then booted into Windows itself and noticed a bit of lag, so I naturally opened up HwInfo to check the temperature stats and THIS was genuinely the face that I pulled.

I was genuinely a bit scared because my PC sounded unhealthy (due to the fans) and I’d never seen temps maxing out at 90 degrees celsius AT IDLE before. I mean, they did “only” average 71 degrees for the first 10 minutes of turning my PC on, which (in some ways) isn’t too bad, I guess, but that’s still very high for a desktop PC with a good quality Noctua cooler.

4K Gaming With Zero TIM (Sniper Elite 5)

Sniper Elite 5 showing 43 FPS rates
Sniper Elite 5 showing 43 FPS rates

But because I’m a mad lad, I then decided to do some 4K gaming in Sniper Elite, before running some stress tests – and THIS is where the problems started. Y’know… actually using the PC. So, I loaded up Sniper Elite 5 and I had all the graphical settings maxed out. I also have VSYNC enabled and the game usually maxes out at 60fps no problem, but I did start seeing FPS drops quite frequently. I even missed a few shots here and there which was NOTHING to do with my lack of ability. Honest. It was totally just due to the missing thermal paste. Early on I saw FPS drops down to the low 50s, and later on I was seeing frame rates in the 40s. While this might not SOUND too bad for 4K gaming (especially since I was running with zero thermal paste), it’s still quite low considering that I usually get 80 to 90 FPS (when disabling v-sync). In other words, I WAS seeing half the frame rates in this case.

I kept track of the CPU temps using HwInfo by resetting the counts before launching the game and you can see that temperatures averaged 88 degrees – and peaked at a whopping 96 degrees. The maximum operating temperature of this Ryzen CPU (the 5900X) is 90 degrees, so clearly this wasn’t good. I’ll talk about whether these high temps could have damaged my CPU later but I wanted to quickly show the other two test results first.

Prime95 Torture Test

So next up I ran the “torture” test in Prime95. Young-at-heart PC builders like me WILL naturally know Prime95, but if you’ve never heard of it, it’s basically a free stress testing tool that maxes out your CPU at 100% so you can test out overclocks and system stability. Actually, I SAY that it maxes out your CPU. It turns out that if you’re a total pillock like me and you remove all your CPU’s thermal paste, a variety of safety measures within the motherboard actually kicks in and STOPS the CPU from running at its maximum speeds. In other words, the “100% CPU” test that I was running was only resulting in below 40% CPU Usage. Notice how the frequency is at just 1.4 Gigahertz too?

Prime95 in the background with HwInfo and Task Manager in the foreground
Prime95 in the background with HwInfo and Task Manager in the foreground

Well this CPU is meant to run up to 4.8 Gigahertz (at boost), so what gives? Well THIS is thermal throttling. People talk about it a lot, but you can see a clear example of it on-screen now. My CPU temperatures were running at 90 degrees celsius (as you can see in HwInfo) and because this is the maximum rated temp for my CPU, the motherboard’s thermal protections kicked in and downclocked the CPU. It’s essentially doing the OPPOSITE of Intel Turbo or AMD Precision Boost, which makes the CPU run FASTER as long as the CPU isn’t too hot. So that’s kind of interesting and it explains why I started to see FPS drops in Sniper Elite 5 – because while that’s a GPU heavy process (because, y’know, it’s a game) there WILL still be various CPU processing required – and the CPU was being throttled all the way down.

4K Video Rendering On My 24 Thread CPU

Finally, I did a 4K video render in Premiere Pro and THIS always stresses my system out a lot – more so than Prime95, in-fact. CPU temps again hit an average of 90 degrees (with a peak of 91) and while video rendering usually maxes out my CPU, in this case it was only around 50 to 60% usage – with a frequency of BELOW 3 Gigahertz. So again, thermal throttling took place. You can literally see the point in time when the throttling protections kicked in – Premiere Pro started ramping up and CPU usage was heading to 100% (as expected) BUT because temperatures got too high, the CPU frequency immediately fell from over 4 Gigahertz down to under 3.

My CPU being thermal throttled during a Premiere Pro 4K video render
My CPU being thermal throttled during a Premiere Pro 4K video render

Motherboard Safety Measures

The actual ASUS TUF Gaming B550M Plus motherboard
My ASUS TUF Gaming B550M Plus motherboard

So that’s actually pretty interesting to see: the Ryzen CPU comes “hardcoded” with a max operating temperature and the motherboard then helps to enforce this by making the CPU a massive bottleneck, essentially. There WAS actually a time when you could  disable this protection in the BIOS, but nowadays that option has been removed – thankfully. If I HAD been able to disable it, somehow, my CPU would have probably ended up getting damaged or even bricked. My motherboard’s VRM might also have been damaged in the process.

Luckily, though, these failsafes ARE in place to protect both the CPU and also the motherboard. There doesn’t seem to have been any long term damage due to running my computer for an hour or so without any thermal paste. I have done lots of 4K gaming and video editing since these actual tests without any crashes, so fingers crossed I’m good. Maybe if I had tried running Prime95 for days on end, something might have eventually got damaged – but this is my main PC, I love it, and so I really wasn’t willing to run it for a week without TIM (for example).

Comparing To ‘Normal’ Temps

Comparing all results including running with no TIM
The orange and (no TIM) dark green (new TIM) lines show my before and after results

I should also point out that while I “only” use an air cooler, the super high temps that I experienced WERE 100% down to the lack of thermal paste. My air cooler is actually a highly engineered Noctua BEAST and it leads to some really low temperatures. In general (when I actually HAVE thermal paste!) my idle temps are 39 degrees, and this then rises to the 50s and 60s in my other tests. So the fact that I was seeing 70 degree temps at a minimum, but mainly averaging at 90 degrees (which shows just how important thermal paste actually is).

cropped A picture of me Tristan
About Tristan Perry

Tristan has been interested in computer hardware and software since he was 10 years old. He has built loads of computers over the years, along with installing, modifying and writing software (he's a backend software developer 'by trade').

Tristan also has an academic background in technology (in Math and Computer Science), so he enjoys drilling into the deeper aspects of technology.

Tristan is also an avid PC gamer, with FFX and Rocket League being his favorite games.

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