Expected Temperatures of a Watercooled 4090FE?

[Mysterae_]

I've noticed that the temperatures of my watercooled 4090FE (Watercool Heatkiller block) have been increasing lately to higher than I would expect for a watercooled part:

Even the coolant which goes to an external MoRa3 to be cooled is exceeding 42C (not shown above) which I think is also too high but is an indicator that it is carrying heat.

Compare that to before, playing the same game and settings, even with a higher core frequency and power draw. The image below was before I monitored the water temperature but I know it wasn't exceeding 40C as the D5 Next overtemp alarm didn't go off.

Are these typical temperatures for a watercooled 4090? Do you think the 4090 needs to be remounted/repasted?

 

[Mcnumpty2323]

I like the display
Coolant temperature does seem high
Assuming your ambient temperature isn't
Also very high?

Is that cpu and gpu in the loop?
Only got a 3080ti and a 5950x in mine
But coolant temperature this time of year on mine
Is just over 30c
Though I have a voltage curve on gpu
And lowered it's power a bit
Is yours flat out?
Or done similar to voltage and power?

Edit
Looking at the 2 pictures
Yeah that's a fair difference in temperature
Assuming both under same conditions
Possibly does need repasted/remounted
Assuming its clear coolant?
Otherwise could also be micro fins blocked

 

[keenan]

At 45°C it doesn't seem too outrageous.

If the coolant is heating up along with the GPU then the mounting is fine! It's the dissipation that could be an issue?!

Have you checked the radiator/s or intakes for dust buildup? Changed the fan speeds at all?

 

[Mysterae_]

I like the display
Coolant temperature does seem high
Assuming your ambient temperature isn't
Also very high?

Is that cpu and gpu in the loop?
Only got a 3080ti and a 5950x in mine
But coolant temperature this time of year on mine
Is just over 30c
Though I have a voltage curve on gpu
And lowered it's power a bit
Is yours flat out?
Or done similar to voltage and power?

The CPU (13700k) is indeed in the loop and is auto OC'd by the BIOS but always has been, but games consume no more than 100W power. The 4090 is at stock settings.

Ambient temperatures have increased slightly, but I position the external radiator so the heat goes outside which increases the water in/out delta by quite a bit!

 

[Mcnumpty2323]

Yeah given that it's only 9c here outside
That should help considerably
The temperature difference between both photos
Definitely says something is up
Shame no flow rate to also compare

As keenan said check for dust in radiators
But with external rad that should be pretty easy to see
How longs the block been on the gpu?
And what sort of thermal paste did you use?
And no sign of clogging in micro fins?
Pump speed looks over 3k rpm so no issue there

 

[Mysterae_]

At 45°C it doesn't seem too outrageous.

If the coolant is heating up along with the GPU then the mounting is fine! It's the dissipation that could be an issue?!

Have you checked the radiator/s or intakes for dust buildup? Changed the fan speeds at all?

So 45C isn't that bad?! You could have a bath in it at that temperature!

The radiator is as clear as a whistle as it's only just been rebuilt a month or so ago. I increased the radiator fans by way of a fan curve associated with the coolant temp when I first saw the coolant get over 40C.

When I positioned the radiator at the window to exhaust it's heat outside you can feel how warm the tube is to the radiator and how cold it is coming from it. Yet the 4090 seems to be getting hotter.

I'm wondering if pump speed is a factor.

 

[keenan]

What's your current pump speed? Maybe increase it a bit and see if the temps come down..

 

[Mcnumpty2323]

Says 3285rpm on first photo for pump?

 

[Mysterae_]

Yeah given that it's only 9c here outside
That should help considerably
The temperature difference between both photos
Definitely says something is up
Shame no flow rate to also compare

As keenan said check for dust in radiators
But with external rad that should be pretty easy to see
How longs the block been on the gpu?
And what sort of thermal paste did you use?
And no sign of clogging in micro fins?
Pump speed looks over 3k rpm so no issue there

Yeah, shame about no flow rate; the D5 Next gives the option of water temp or water flow rate, not both.

The block has been fitted since mid March going by my build log (which I was going to conclude before this), so a bit weird for it to start playing up now.
I used Artcic MX-6 for both the GPU and CPU.
The GPU is easy to check for blocks in the microfins, the CPU (EK Velocity2) not so easy!

 

[Mysterae_]

What's your current pump speed? Maybe increase it a bit and see if the temps come down..

Says 3285rpm on first photo for pump?

If my memory serves me right (not at the PC right now) the pump speed of 3285rpm (7W) is about 60% according to the D5 Next.

 

[Mcnumpty2323]

That's no time at all then
Pastes not going to go bad/need replacing
After that short time

And some may say 45c coolant isn't too bad
Since yeah youre putting a lot of watts into it
But what would that increase to in the height of summer

My d5 at max is 4770rpm
So yes got some headroom there
Definitely worth trying more rpm to see
Mine at approx 70--80% doesn't see much improvement
If I go higher
But youre dumping more watts than I am
So it might make a bigger difference

 

[keenan]

I firmly believe your temps are fine! Looking online it seems like some with even 2 x 360mm rads are sitting around 50°C..

Going by that yours are looking on the better side!

 

[Mcnumpty2323]

Did we ask?
How much radiator he has?
Assuming its equivalent to 3 x 360mm
Or even 3 x 420mm
That's plenty radiator especially given its external
So doesn't suffer from heat inside the case too

 

[keenan]

Did we ask?
How much radiator he has?
Assuming its equivalent to 3 x 360mm
Or even 3 x 420mm
That's plenty radiator especially given its external
So doesn't suffer from heat inside the case too

We actually didn't..

Also, is it one loop or two separate loops for CPU/GPU?

 

[Mcnumpty2323]

I assume its one loop
No mention of a second pump
And it's one large external radiator
Though technically yeah you could run 2 loops into it

It still comes back to the large difference
Between those 2 photos and gpu temperature
In them
If its same circumstances for both of them
Why such a big temperature difference in just over a month?
If they built it today
And said why is my coolant 45c
Then fair enough maybe we could say that's normal for what you have

 

[keenan]

I didn't even look at the first photo.

This whole time I thought his temps were 45°C when in actual fact they are 61°C..

Geez, it's been a long week!!

 

[Mysterae_]

We actually didn't..

Also, is it one loop or two separate loops for CPU/GPU?

I just wrongly assumed that folk clicked the link in my sig .

It's a simple two block loop, in and out to external radiator (4x180 fans) and single D5 pump & reservoir:

With two T30's blowing down cooling the case internals:

It still comes back to the large difference
Between those 2 photos and gpu temperature
In them
If its same circumstances for both of them
Why such a big temperature difference in just over a month?
If they built it today
And said why is my coolant 45c
Then fair enough maybe we could say that's normal for what you have

This is what it boils down to. The big jump in both coolant and GPU temperatures from March to now with nothing changed in regards to the watercooling.

I think I'll do some testing with Furmark so that I can have a stable load and tweak various things before stripping down and repasting.

 

[momo56]

Sounds like a flow issue, 42c fluid temp is too high.

Hard to make out but looks like you got a heatkiller block on the FE ?

Going from the first pic. 30 degree difference between fluid temp and core is a concern. Check if your fins are blocked or thermal paste pump out.

I’m using a heatkiller strix and mora420 myself, delta between fluid and core temp is around 14-15c. About 7-8c difference between the core and hot spot.

 

[Mysterae_]

Sounds like a flow issue, 42c fluid temp is too high.

Hard to make out but looks like you got a heatkiller block on the FE ?

Going from the first pic. 30 degree difference between fluid temp and core is a concern. Check if your fins are blocked or thermal paste pump out.

I’m using a heatkiller strix and mora420 myself, delta between fluid and core temp is around 14-15c. About 7-8c difference between the core and hot spot.

Thermal paste pump out is the thing I'm concerned about and why I was thinking about a re-paste. A hotspot temperature of 75C on a watercooled 4090 seems a bit high.

It does sound like there's an issue then?

 

[momo56]

Yes there’s an issue. I would increase your fan speeds and pump to 100% see what core temps are like at 30c fluid temp and work from there.

Nice build btw. Love SFF and external rads too.