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*** Official AMD 7990 Owners Thread ***

BuzzLloydyear said:
GPU1 - 45c and GPU2 - 36c

As for the guy who mentioned voltages, I have tried multiple things, synchronised and unsynchronised settings in Afterburner and manually set voltages, voltage control off in afterburner. I am trying to get control of the temps and make them closer to what they should be from stock settings. I have lowered the voltages before and I have to be honest, it didn't appear to make the biggest difference in the world.
Click to expand...

Cat could be onto something you know. Does your card sag at all? Can you prop it up with something to see if it has any effect on the hot core? Maybe something gently pushing it towards the cpu.
 
Th0nt said:
Update:

Had some spare time so I reckon the AB forgets to re-apply the voltage or another program takes charge instead.

I put a desk fan to the side and when under-volted the temps of both cores are around 68-70. Core 0 only 2c above the other which is far more encouraging - no HW errors at the same hash rate.
Click to expand...

Right can the improvement. Don't know what's going on unless if you mine a different coin it affects the card differently?

GPU-Z shows the voltage at being 1.17, even though I am trying to set it lower through cgminer config and also AB. I have rebooted but the core 0 has gone back to operating at higher temps than core 1 again. Unsure as to why.
 
Right temps are hella close now (considering what I have faced). I think that the Akasa Thermal Compound is negatively effecting my temps so I will switch back to the Arctic Silver compound and test it then. If I can get the gpu's slightly lower, then I will call it a result well earned.

Below is a heaven screenshot after about 10-15 mins of running.

Screenshot
 
I will throw one up a little later, I am still testing different amounts of elevation to see which is ideal, using the oldest, flimsiest piece of wood I have ever seen, that's because it's the only dry piece I could find in such short notice, when I get the measurements for perfect elevation, I will use some better wood and craft it properly, maybe adding some sort of rubber on the end to improve grip on the plastic of the card as it's very smooth plastic and the wood has a fancy for sliding away from the card when positioning it.

For now I will give a mental image of what I have done.

Measured the distance from the card to the bottom of the case. Got an old piece of wood, which happened to be the only dry piece of wood in Wales I think. Cut it several millimeteres longer than the distance I measured from the card to the bottom of the case and eased it on the far end (away from where the card is screwed in).

There is not a great deal of room for placing it as the face of the car is about 90% fan so it's right up on the edge and due to the smooth plastic and the rounded edge it is a little too slippery for my liking, hence why I will try to add some rubber on the end to give it some more grip and avoid any slips should the case get knocked etc.

Will get a photo up as soon as I can to give you a better reference, but hopefully you understand what I did from that.
 
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Looking for a 120/144Hz monitor to put my 7990 to use :)
Though I also want a new motherboard and CPU :o I hope I can find some good deals.

I missed out on a 3930k for £280 :(
 
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BuzzLloydyear said:
I am going to give this a few tests, but it appears, propping the card up is a step in the right direction so far. It's not ground breaking and the gap is still big, but it may well be improving my temps.
Click to expand...

Let everything cool down and start the tests.

These cards definitely suffer sag, even with the back plate on. This thread has some of my posts on it back in the early posts.

I fought uneven temps on the GPU's for ages and found that in order the following were the culprits.

1. Uneven voltage settings in AB and Trixx
2. Card Sag
3. Thermal Paste

All of these contributed to the problem.

The temps on my 2 x 7990 are never more than 3 degrees per card which is acceptable under water considering one is cooled after the other per GPU.
Of course my 2nd card in the loop is higher, about 10% as it has water heat from 1st card in CX .
 
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OK buzz, will wait for more feedback and some pics. In the mean time as long as this undervolt sticks I am just going to add a case fan. Other option is to raise the case and use the floor to mount some fans to blow up onto the card directly.

I have a carbide if you look at the base you can remove the HDD caddies and would be generous clearance for airflow. What you think?

 
Catanonia said:
Let everything cool down and start the tests.

These cards definitely suffer sag, even with the back plate on. This thread has some of my posts on it back in the early posts.

I fought uneven temps on the GPU's for ages and found that in order the following were the culprits.

1. Uneven voltage settings in AB and Trixx
2. Card Sag
3. Thermal Paste

All of these contributed to the problem.

The temps on my 2 x 7990 are never more than 3 degrees per card which is acceptable under water considering one is cooled after the other per GPU.
Of course my 2nd card in the loop is higher, about 10% as it has water heat from 1st card in CX .
Click to expand...

Fell asleep watching extra time of Sunderland vs Chelsea so have to resume this today. When you say prop the card up, how much elevation are we talking? Right up as far as physically possible without causing damage, or just a minute amount? I get improvements with my current strategy. I can't help but feel there are a few more c's I can shave though.

I am currently using multiple pieces of wood with a small variance in length and trying to find a sweet spot, whilst they all seem to bare improvement, they all seem to be yielding similar results, or at least close enough to not be able to tell if difference.

I put Arctic Silver back on this morning and it's improved temps a little already, it takes a long time to set, but it's already a small improvement. Not the 8 degree's I was thinking, but 4-6c on gpu2 definitely. Hard to say with gpu1 as the propping up is obviously effecting the temps too.

I have lowered the voltage to 1135mv, this has allowed me to stay around 85c on gpu1 at worst case scenario in Heaven, which is a damn site better than the near 100c temps I was getting earlier in the week. I feel I am still missing a few more degree's somewhere though, so hopefully with a bit more experimenting I can find that and keep gpu1 in the low 80's that will satisfy me that the card is not as dodgy as first thought and go throw some money at water cooling the beast.

It was nice to do a 20 min run of heaven and not hear the fans kick up to hella fast levels when the card hit's above 93c though.
 
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