3090 FE high temps low performance

[otester]

Since I got it in late 2020, I had to power limit it to prevent the memory overheating (common problem), after the warranty expired I started looking into how to fix it, over last few months I've tried repasting/padding it 4 times, the memory temps are very good now (max 80C) but avg/hotspot keeps maxing out at 90C/100C respectively, the delta is 10-11C.
In 3dMark Steel Nomad I get ~4500 (apparently average is at least 5000). In heaven I also get ~10% bellow average as well.

1st time - MX-4 and ThermalRight Odyssey 1.5mm pads.
2nd time - ThermalRight TFXand Gelid Extreme 1.5/2mm front side, Gelid Ultimate 1.5mm on back side.
3rd time - PTM7950 and Gelid Extreme 1.5/2mm front side, Gelid Ultimate 1.5mm on back side.
4th time - PTM7950 and Gelid Extreme 1.5mm front side, Gelid Ultimate 1.5mm on back side.

Using this tutorial: https://www.reddit.com/r/nvidia/comments/mmzri2/3090_fe_thermal_pad_mod_cutting_template/

Also watched loads of video on how to paste, apply ptm correctly, made sure to remove plastic film off pads before applying, carefully align pcb when putting back together etc.

The temps shown after others repaste/repad show avg/hotspot in 60's and memory around 80C so I think either I am doing something wrong, missed something or maybe the vapor chamber has failed? Any ideas?

CPU: 9800X3D
RAM: 64GB DDR5-6000

 

[Doctor]

If you did everything else correctly maybe you aren't getting the pressure even when reattaching the cooler?

 

[otester]

If you did everything else correctly maybe you aren't getting the pressure even when reattaching the cooler?

The delta after the 3rd time with 2mm pads was 15-20C which makes me think it wasn't even but at the moment its 10-11C which makes me think it's even but maybe overall pressure is wrong, the X-bracket screws are designed to not allow overtightening, I only did them up until they stopped turning, here are some aftermath pictures:

MX-4 (spread using spatula as shown in jay2cents repaste video)
TFX (X + 4 dots pattern, probably used too much)
PTM

 

[Doctor]

Looks fine to me, I repasted my 3090 strix in the summer and didn't see any issues, dropped temps 5C from the 4 year old paste that was in there.

 

[Disco_P]

From doing these mods in 2021, I remember that the firmer gelid pads would prevent the cooler from applying the necessary pressure against the die for good conductivity.

I can't remember which pads were the squishier ones that worked well.

Also cut your pads, one per module with a slight gap between them to allow them to spread out in all directions

 

[Rogueywon]

Those hotspot temps look very high for a 3090FE. If you've already tried the thermal paste, I'd be looking for potential other causes. Is your case sufficiently ventilated? Is there anything else that could be chucking heat over the GPU? Failing that, it may well be the vapour chamber.

 

[otester]

Looks fine to me, I repasted my 3090 strix in the summer and didn't see any issues, dropped temps 5C from the 4 year old paste that was in there.

The AIB cards look a lot easier to deal with, the 5090FE looks like a nightmare this time around if you have to open it given it has liquid metal.

From doing these mods in 2021, I remember that the firmer gelid pads would prevent the cooler from applying the necessary pressure against the die for good conductivity.

I can't remember which pads were the squishier ones that worked well.

Also cut your pads, one per module with a slight gap between them to allow them to spread out in all directions

On the front side, Jay2Cents tried 2mm, good VRAM but bad avg/hotspot temps, then 1mm giving waterblock like temps (~55c) for the avg/hotspot, the VRAM went upto 100C, he then settled with 1.5mm, I think he was using EK which were quite squishy. (Video)

Others have also mentioned having issue with 1.5mm on the front side, having to pre-squish them a bit.

I've ordered some Upsiren 21W/MK 1.25mm pads, might be the perfect size.

Those hotspot temps look very high for a 3090FE. If you've already tried the thermal paste, I'd be looking for potential other causes. Is your case sufficiently ventilated? Is there anything else that could be chucking heat over the GPU? Failing that, it may well be the vapour chamber.

CPU 360 AIO (3 fan) intake, 2 exhaust fans rear/top of case, tried it with side off and makes no difference, the idle temps are 30-40C, seems to just saturate under load. I'm praying it's not the vapour chamber.

 

[otester]

I tried the Upsiren 1.25mm pads (front) and Gelid Ultimate 1.5mm pads (back), reapplied PTM.

87C gpu, 100C hotspot, 84C memory, ~4500 Steel Nomad score again.

I noticed the backplate only gets to ~65C and the fins near fans only 50C. Vapor chamber failed or time for putty?