XFX 7900XT merc 310 high junction temperature

Majestic Fucksquatch said:
Just installed the bykski block with ptm 7950 on my XFX 7900 xtx. Results are attached for anybody interested. First pic is after 20 minutes of idle, 2nd pic is after 15 minute stress test on 3d mark. Before I installed the block I was getting 60c idle with 70c hotspot temps and 80c+ with 100c hotspot temps under load.

View attachment 5932
View attachment 5933
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Out of curiosity, what was the board power setting that you used? Stock? +10% +15%? Which 3D Mark Stress test did you do?

I just recently installed a TG Phasesheet on my Alphacool block on my Merc 310 and I am experiencing very good results. in RAGE Bios mode, (403W) and when I do, I get a peak hotspot temp around 67-69C after a Steel Legend 20-pass stress test. I'm very heppy with these results. I'd just like to compare apples to apple with your test. Thanks!
 
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Hello,
Found this place after acquiring an Eisblock for reference 7900XTX off ebay and struggling with it and I would like to share my findings. First some caveats:
I'm installing this on the Yeston Sakura Sugar card. It isn't documented anywhere but since all the holes line up I can only assume it is using the reference board design.
This card runs aims for a 350W power target.
The Eisblock came from ebay without the 3mm pads for the backplate.
This is my first time ever attempting water cooling.

Initial install was abysmal. I spread my paste evenly as recommended by many and tightened all screws until they stopped against the board. I did not install the backplate since I didn't have pads. Average temps in the 50s and hotspot on the GCD was pegged at 110C in Furmark.

I noticed the bending in the board and backed off all the screws until it was flat against a ruler. This was marginally better, with the GCD hovering around 100C and bouncing off 110C and average temps in the 50s.

After finding reading through this thread I attempted to stack cheap thermal pads against the back of the core and installed the backplate. This was marginally better yet with the GCD hovering in the mid 90s, but still spiking to 105C occasionally. Others have noted that their cards maintain full boost clock at those temps, but this Yeston card seems to start throttling earlier and I could only maintain about 1500mHz in Furmark.

I took the whole thing apart one more time. I reapplied paste and this time just by laying dots on the MCDs and a fat log across the GCD. I reinstalled it using the spring bracket from the original air cooler that goes across the back of the core but with the eisblock screws. Tightened the screws until the bracket was touching the board on all four corners. Did not install the eisblock backplate.
Computer didn't post. Debug light for VGA problem. Sweating, backed off the four bracket screws by one full turn.
Computer boots, card now has an average temp in the mid 60s and a hotspot of about 85C. Raising the power limit to 380W It will now max the hotspot at 90C. Maintains ~2000mHz in the furmark test at these temperatures.

tl;dr, the eisblock for the 7900XTX reference is unable to apply sufficient pressure on the core. Attempting to tighten the four main screws further risks damage to the card. The 1Nm torque recommendation for those screws is absurd. Just use the spring bracket from your air cooler.
 
My hotspot with the stock cooler on my xtx merc was 75c, I had it from 1st release and have never pulled it apart, I have a brutally aggressive fan curve though. Came here to decide what block/pads and whatnot to get, Thank you all for the detailed trials you've had to go through.
 
I am experiencing the same bad thermals to a sapphire nitro + rx7900xt. the hot spot goes way up to 115c! even the 105c isnt supposed t ohappen with water cooling! i have tried repasting with thermal pads in 1.5mm (wrong size but had totest!). changes didnt happen. i used the correct ones then 1mm. The dgrres fell upto 113C. i have refilled the whole waterloop to be sure no air is blocking. but alas. as a water cooling on cpu and gpu it should have been down to at least 80celcius for the gpu and some 95-100 celius for the hot spot. i think something is not correct in the waterblock structure. the airblock i changed it due to lessen the sound of the fans. i think i go back to the air to test last time. please acool retest the waterblock. there seems to be either inadequate water passing in the block or too thin aluminium metal. the back side is ok with the given pads from your company. the card is really hot not on the gpu die but on the left side with the many r15 chokes. there seems to be the hotspot reading from.if the thermals seem better than the water cooling...pitty i wil lgo air and wont recommend the waterblock. let me mention i even changed pump to put a stronger flow...no. pump is on 100% speed.
 
ckinfos said:
I am experiencing the same bad thermals to a sapphire nitro + rx7900xt. the hot spot goes way up to 115c! even the 105c isnt supposed t ohappen with water cooling! i have tried repasting with thermal pads in 1.5mm (wrong size but had totest!). changes didnt happen. i used the correct ones then 1mm. The dgrres fell upto 113C. i have refilled the whole waterloop to be sure no air is blocking. but alas. as a water cooling on cpu and gpu it should have been down to at least 80celcius for the gpu and some 95-100 celius for the hot spot. i think something is not correct in the waterblock structure. the airblock i changed it due to lessen the sound of the fans. i think i go back to the air to test last time. please acool retest the waterblock. there seems to be either inadequate water passing in the block or too thin aluminium metal. the back side is ok with the given pads from your company. the card is really hot not on the gpu die but on the left side with the many r15 chokes. there seems to be the hotspot reading from.if the thermals seem better than the water cooling...pitty i wil lgo air and wont recommend the waterblock. let me mention i even changed pump to put a stronger flow...no. pump is on 100% speed.
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Unfortunately, Alphacool has long since stopped caring about this.
This isn't their first (or last) unsuccessful product. I previously encountered the first revision of the VPP pump and its noise issue. The community also tried to solve this problem with more enthusiasm than Alphacool..
But to be fair, the water block from Bykski performed even worse.

Multi-chiplet design of video cards harms the cooling process. I had similar but more quickly resolved issues on a Vega 56 in 2018.
Again, modern video cards are getting better and better coolers, so water blocks are becoming increasingly useless.
 
I owned RX VEGA 64, it was the air cooler limited edition. So had GPU die surrounded by HBM, it was a molded die. So it had filler between the GPU die and HBM. I used an EKWB waterblock for many years, may have been like 4 years or so, then sold the card with the waterblock.

Not once did I ever redo that card, first was final fit whilst in my hands for several years.

Also owned other GPUs with waterblocks, currently I have a RX 6800 XT Pulse coming upto 5 years in use, Bykski waterblock. Not once since first fit have redone that waterblock.

I am redoing my RX 7900 XTX MERC again. The strangest thing is my first fit when got the block lasted longest, but I had more thermal pads on rear then came with card, so much so that the back plate had a bend. My subsequent refits lasted less time, I think I am on my third or fourth refit.

I went over to putty between VRAM/MOSFETs, luckily it can be reused and so not wasting thermal pads on refitting.

As much as the waterblock on first receiving felt weighting, well designed and built, I no longer think that, and saying I am disappointed is an understatement.
 
I did the repaste, I've been using UPSIREN UTP-8 putty on VRAM/MOSFETs.

Loaded GPU with Memtest Vulkan performance VBIOS:-

i) -10% Power Limit, IDLE link, 4min link, 10min link.

ii) no adjustment to Power Limit, IDLE link, 4min link, 10min link.

It isn't performance of the block I have a disappointment, above is a fully enclosed setup, slim 2x360mm (as stated in this post), it's the fact I have to repaste every so often that is a total disappointment. Especially when a Bykski block would have cost me half the price...
 
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