Expected Temperatures of a Watercooled 4090FE?

[Mysterae_]

Damn I love this thread. Nostalgic old school troubleshooting with some awesome thermal pics and a happy conclusion.

I mentioned this in a thread a while back but ptm7950 is the future when almost hardly any of us are pushing for that extra 0.1% performance of LM 24/7 today - especially on something like a GPU.

It helps us all learn, no point in keeping the knowledge to ourselves!

Oddly it was the first time I had heard of PTM7950. I have some on order now should the temperatures go bad again - it took about a month to occur so I'll be watching closely. That's why the sensor panel/screen at the front of the PC is so good, without it I could have been blissfully unaware.

Since this is the watercooling subforum I thought I share a little clip that I added to my build log of the coolant being filled and bled - it gives a good indication as to the flow rate of the D5 pump attached to the D5 Next and Utilitube.

There was a lot of air to get out the system!

 

[Mysterae_]

This thread made me want to check my 4090. Was surprised since core/ hotspot delta was only 13c.

First time this has happened to this extent with Kryonaught. Guessing the 1000w bios didn’t help things.

1000W bios?! You're brave!

Your images are very similar to mine, that distinctive "gecko feet" pattern that the thermal paste makes as it's pumped out I presume.

Did you use PTM7950 on your reassembly?

 

[Mysterae_]

That certainly is a lot of air
At the beginning of the video clip
It looks like the coolant has separated /settled?
Darker blue at the bottom of the res than the top?

I was hoping someone would ask about the weird layered coolant in the reservoir .

The stuff at the bottom of the reservoir was a fresh application of Halfords finest engine coolant/antifreeze (glycol) with de-ionised water sitting / suspended on top of it, it just hadn't mixed yet. It's jiggling around at this point due to the vibration of the pump.

Once the air that was present in the computer eventually made it's way to the pump/reservoir it allowed the coolant to replace it; you can see the level in the reservoir go down quite quickly.

Now that the coolant and de-ionised water are thoroughly mixed there's no strange suspended water effect in the reservoir anymore, which is a shame .

 

[Mysterae_]

Could add alcohol
And have 3 layers lol

What ratio of glycol to water are you using?

Would some oil make 4 dimensional?!

I'm not sure of the precise ratio of glycol to water I'm using, probably something in the 1:4 (20% glycol) range - enough for the water to turn a light blue .

That ratio has been fine for me in the past, even with the reservoir sat in sunlight for part of the day.

 

[Mysterae_]

How are things going with the repaste, or did you go the PTM 7950 route.

Im having a similar issue with my 4080, but its took ~9 months. Started mid 40's load with hotspot 6-8 degrees above. now im in the mid 50's load with the hot spot ~20 degrees above. This is with the thermal grizly that came with the EK block.

It's still good after the repaste, haven't needed to apply the PTM 7950 yet. I've been keeping my eye on it!

Your problem does sound similar, if it's the only temperature that's gone up then that's where to check. Is your 4080 watercooled or stock?

 

[Mysterae_]

Its water cooled. Very simlilar system to how you are doing yours with external rad etc.
Initally the temps were quite good on the 4080 when I first put the block on ~9 months ago. I used the paste that came with the block, Thermal grizly which I thought was decent.

Where did you get you PTM 7950 from ? I can only find it on ebay and amazon with a few comments saying its fake.

I got mine from ebay and to it's authenticity, I don't know as there's no Honeywell branding.

I see the LTT Store has some type of it but you'll have to decide if you want to give that muppet money and import it from the US.

 

[Mysterae_]

Anyway ended up giving Kryosheet a go and it worked surprisingly well. About the same temps as Kryonaut so pretty impressed.

Will be interesting to see your temperatures are after a few months, please let us know.

finally thought sod it and ordered some PTM 7950 from ebay.

After a bit of messing about (school boy error, got the feed and return to my external pump and rad back to front ...lol ) Temps are now as good if not better than compared with the TG hydronaut installed ~9 months ago.

Hydronaught after 9 months
Amb 22.6, Water 27, Peak GPU 52.2, Peak H-Spot 72.3

Now with the PTM7950
Amb 22.5, Water 26.9, Peak GPU 48, Peak H-Spot 56

Both with 20 mins Dirt5 peaking at ~300 Watts. Not the most comprehensive test but it cleary shows its works

Just a shame that OCUK doesn't sell this PTM 7950 as I would have rather gave them my money.

That's some good results, tempted to take my system apart and give it a go.

You are right that OCUK should sell the stuff, if Linus can sell it then surely OCUK can too.