1 : Anonymous2021/09/19 18:33 ID: prdlfm
2 : Anonymous2021/09/19 19:17 ID: hdhz9sx

It's a lottery but most have some deformation.

I needed to lap my 1800x and my 3900x but gladly my 5900x is totally flat.

And yes, if they're not perfect it can really affect your temps. Even more if you use liquid metal.

ID: hdisaj3

My 3600 had worse temps than my 5900x and that bothered me. This might explain why.

3 : Anonymous2021/09/19 18:39 ID: hdhtf81

Since my 5800x purchase, I have had what a lot of people have been complaining about. Under any benchmark ran, my CPU just hit 90C and stayed there. Gaming I would see ~70-75C (MSFS2020). Everyone just said that the Ryzen 5800x just runs hot...and it does...but I finally fixed the physical issue with the CPU that was causing the higher then expected temps. Here is what I was running before and the scores I saw:

Cooler: I have two 240mm EKWB rads(in series) and a "basic" EKWB CPU block.

CPU: Ryzen 5800x, PBO manual, power motherboard, 150Mhz override. XMP 3600Mhz 1800Mhz, FCLK 1:1

Before Fix: R23 15178 MC, temp 90C sustained, PPT 130w, TDC 84.5A, EDC 151A, Boost all core 4.45Ghz sustained (CO -10 core 0,2 / -20 rest) MSFS2020 ~70-75C

After Fix: R23 15861 MC, temp 77C sustained, PPT 145w, TDC 91A, EDC 158.4, Boost all core 4.7Ghz sustained (CO -10 core 0,2 / -20 rest) MSFS2020 ~60-62C

The fix?

Sanding the IHS corners flat. Two IHS corners were .3mm higher then the center of the IHS!! The other two were .2mm higher. That will do it. I know it is concave by default....but that was extreme. If I put the IHS down on a flat surface...light shown through it no problems. All the thermal compound in the world will have issues with that much space.

I put a 1000 grit wet sand paper on a sheet of glass and did circles with the CPU until I stopped seeing light under the IHS (like it is supposed to be). That picture of the CPU shows that only the IHS corners were making contact with the sand paper. If you look at the waterblock picture....it was only touching the IHS at the top of the ridges on the .3mm higher side. NO OTHER PART OF THE WATERBLOCK WAS TOUCHING THE IHS due to the uneven surface!!!

I had re-seated this block at least 10 times and I had the same result every single time with multiple types of paste. Never did any good. Now that I know the IHS was so off....everything I saw made sense now. With the very uneven IHS...good thermal contact was absolutely not possible.

I am writing this post as a PSA due to all the people saying that the temp hitting 90C right off the bat in bench marking is OK. It's not...it is NOT supposed to do that. Ryzen may be good up to 90C by spec....but it shouldn't sit at that right when you start up any benchmark...it just should not. If any of you are having this same issue and you know your cooling solution is good....check your IHS. You probably have the uneven raised corners like me and the contact with the cooler is crappy due to it. I also don't have the spikey temp from idle issue near as bad as before.

AMD really needs to do better QC inspection on their IHSs IMO.

ID: hdidw7a

Interesting. Makes me wonder if this is what appears to be wider silicon variation in the 5800X than other Ryzen 5000 SKU's in Passmark.

Next time I repaste my CPU, I will look at my water block for any evidence of ridges or unevenness. But I don't think I have this issue, as my temps aren't really much hotter than my previous 3600X in most scenarios. In fact it's often 2-3c lower in games than my 3600X was (49-52C in most games, more threaded games sometimes break 60c), but Handbrake and Cinebench are both about 4-5c higher than the 3600X.

Your R23 results are now the same as mine, at the same 77c as well. (-10 CO all-core) My chip has never hit 90c in it's life.

ID: hdiiq90

I have thought about that and it makes sense.

The 5800x has the highest heat spot of any of the 5000 line. The 5800x has a hotter(leakier) CCD becuse it has more TDP headroom to work with. The 5900x only has 6 cores working per CCD and the CCDs spread out which moves the heat around. The 5950x has to have 2 pretty good(non-leaky) CCDs to stay under the TDP limits. So the 5800x would be the hottest per area of the 5000 line.

Add a bad thermal coupling to random ones due to the random IHS un-evenness...and the scores would probably be all over the place for it over the other 5000 cpus.

4 : Anonymous2021/09/19 19:38 ID: hdi2f9g

This is a good reminder that AMD does occasionally let a not-very-flat Chip/IHS go out

and its worth asking during troubleshooting how flat is a new chip?

5 : Anonymous2021/09/19 19:00 ID: hdhwnxq

When I got my first r5 3600. I posted about it having ridges. I had the same problem with my ryzen 1600x. I just took a fine Emory stone to the edges and filed them down. Done in a way you wouldn't really notice the hand work. It has been an issue posted all over with the ryzen line.

6 : Anonymous2021/09/19 20:11 ID: hdi7iq3

It seems like it wouldn’t be hard to sell CPU’s that are perfectly flat? Why don’t they put more QC into things like this?

ID: hdilvc7

Mine is still not flat TBH. I never expect a IHS to be pure flat....but...

.3mm on two of the edges and .2mm on the other two left a larger space then there should be between the IHS and my block. Thermal compound can only be so thick. The two sides being different heights also means my block can't sit square (as you can see in the pic...the ridge of the .3mm side dug into it) so the pressure on the thermal compound was bad too.

I just sanded it to not allow light under the IHS when placed on a flat surface. Before, I could shine a light on one side and see it on the other no problem.

AMD doesn't need to make them 100% flat...but they do need to do a better job of making them close.

ID: hdihhmq

Perfectly flat is not going to happen with a mass produced part. Even really flat would add a considerable cost. Unless it's causing the part to not function as advertised, then it's flat enough.

ID: hdi88oj

The arent supposed to be flat.

ID: hdi9vqv

They aren’t supposed to be concave either

7 : Anonymous2021/09/19 20:41 ID: hdibz0q

I've been beating my head against the wall with my 5800x temps and for smiles and grins I just did this and my temps are down considerably. Idle temps are down about 5 degrees. I'm still running up to 90 on R23 but it doesn't just hit that right out the gate anymore.

Thanks for the PSA.

8 : Anonymous2021/09/19 18:35 ID: hdhstxs

Lap it down.

ID: hdhu4yx

Ha...that's basically what I did. I just didn't want to do so much to remove all the txt incase I ever have to RMA it. I just watched the txt area and stopped when the sanding starting getting close to it. That made all the difference in the world temp wise.

ID: hdhxg3m

If you lap it, your warranty is gone. Know your risks, make your choices. It’s unreasonable to expect AMD or Intel to warranty a physically modified CPU.

ID: hdhu9eh

If you even scratched it they're not gonna rma it...

9 : Anonymous2021/09/19 22:10 ID: hdiog8o

Very interesting read. Thank you for sharing.

I must admit I have been that person before, telling people 85c on their Ryzen 5800x,5900x, and 5950x is normal. I would of said 90c is kinda high tho even it won't damage the cpu yet.

But that brings up a very interesting point, because if you are hitting 90c super quickly, and themral throttling off rip, then you are leaving so much performance on the table.

I would be nervous to recommend to someone to try your method if they where experiencing the same issues, especially if that person isn't the most knowledgeable, but it's good info to know nonetheless. Perhaps if a person is experiencing the same exact issue as you, then they should return their CPU while they still can because they may have an uneven IHS off the rip

ID: hdiue2g

There are two main things I would look for if someone was describing this issue to me if it would help or not.

If they take a known, flat surface(glass works great). Place a black piece of construction paper on it. Place the cpu IHS side down on the paper. Shine a bright light on one side. If you see the light through the IHS/paper section...you have an off IHS. Your block shows evidence of one side digging in and no marks on the other. That tells you the IHS is off also.

I used a set of digital calipers to measure my edges for completeness...but I already failed 1 and 2 above.

10 : Anonymous2021/09/19 23:21 ID: hdiy1ap

Downvote that nail

11 : Anonymous2021/09/19 21:05 ID: hdifftc

Next time clean your nails.

ID: hdijvia

AHHHHH...I knew one of you would see that.... 🙂

It was old thermal grease up under my thumb nail. I though I got it all off. I noticed it AFTER the picture and I had put the CPU back in.

I can send you a pic of my now clean thumb if you like? haha

ID: hdijhrd

I’m pretty sure that’s the sandpaper residue, give them guy a break.

ID: hdirhl6

Why do you care? OP is busting their ass to make their hardware better AND sharing PSA to the community and you're sitting at home talking shit? It's easy to have clean nails being a keyboard warrior.

12 : Anonymous2021/09/19 20:01 ID: hdi63f2

I have some knife sharpening stones… I wonder why people don’t use those? I would trust a stone more then sandpaper…?

ID: hdia08v

Sandpaper works if you continuously change your grinding direction in a regular pattern. That way you even out errors.

Same thing applies to stones aswell. And sharpening stones need honing to retain a flat surface which you can do with, you guessed it, sandpaper on a flat surface (like glas).

Of course this isn't nasa level precision but usable.

Edit: I also meant to say: yes you can use a stone.

ID: hdiaxzt

This was 1000 grit, wet sandpaper. Basically a paper sharpening stone. Small circles on a piece of flat glass without pressing on the CPU means only the high parts are touching the sandpaper. 1000 grit wet means you cannot take much off at a time and is the gentlest on the material. I did this as I needed it as even as possible. A stone to each end at a time has the chance of taking too much off one side and not the other.

ID: hdiyeqa

Because with a stone as you sharpen things on it the wear is not even and makes the surface not technically flat anymore. With a piece of glass and sandpaper the glass is always flat no matter how much sharpening you do on it since you just change the abrasive paper element.

13 : Anonymous2021/09/19 22:30 ID: hdir464

Looks toasted lol.

14 : Anonymous2021/09/19 22:37 ID: hdis07w

Isn’t thermal paste supposed to mitigate these sort of issues?

ID: hdivpzl

Yes and no.

The paste is supposed to fill in all the tiny imperfections between the two for a better thermal mating.

Paste cannot bridge the gap of .3mm well. Add to it that one side was higher then the other....and the block cannot exert the correct amount of pressure the paste needs. Thermal pads are the same. You have to have the correct amount of compression on them for them to work correctly.

TLDR: The space between was too big and the different edge heights caused the pressure of the cp

not to be right either.


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