MSI 580 Lightning

[SF3D]

If that is true, we have two very good Lightnings....

We will try to add this additional buffer.

But with my physical understanding it makes no sense, why the card have more problems under heavy load without HS.
Because there is more thermal resistance with HS...

In case the thermal paste between DIE and HS is better then OCZ freeze we used after HS removal and can handle heavy loads better, we have to find a equivalent replacement for the thermal paste.
But then it should be fine even without HS and direct contact between DIE and pot.

Thanks for sharing your knowledge...
Andi

That is true. It makes no sense if we think pure physics.
The situation is very unpredictable with 3000 million transistor working at 1.6V and 1500MHz+.

GPU die will be a lot more warmer with hs on and if you have extra plate between HS and pot, it will be even more warm.
That does make sense, when we think about current flow + GPU operation + temperature.
There is sort of current sweetspot for every GPU depending of the leakage, which will change with temperature.
For that same reason there is also temperature sweetspot.

I could test my DCII card at 1400MHz at -120C when it needed -135/-140C with HS on.
After 1400MHz I got lock ups no matter what voltage or temperature was applied, if there was no HS.
I reinstalled HS and just did same tests at -140C but I raised only voltage and it was scaling.
Then I kept temperature at that sweetspot and raised voltage as far as it helped something (up to 1.62V).

From this point of view we can make conclusion, that voltage is more important for some GPU's than temperature.
You will need to add more voltage to gain clocks because getting colder propably will not help in most cases.
When you don't have HS on, you will go easily too cold and you loose the current/temperature sweetspot.
Then GPU must have some sort of cold issues, which will lead in to crash or lock up. It might be some certain part of the die, who knows.
Usually this will be solved by driver restore.

All materials have some certain heat capacity and heat transfer cabability.
I think the GPU pot's everyone is using are pure copper and the base is quite massive.
The very heavy load from GPU will heat up the first 0.1mm of copper very fast and the GPU will overheat, cause the load is very extreme.
The massive copper block can not transfer enough heat in that very short time and it will cause problems. This will happen in milliseconds/tenths of a second.
When there is two layers of thermal paste and HS, heat have kind of a buffer zone (HS), where it can be transfered rapidly. Then GPU or some part of it will not fail in the beginning of load.
The mass of the HS is a lot lower than the base of the pot and that might be the reason it is better to be there than not.

So getting more cool, is not always so cool!