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Author Topic: 5970 VRM Cooling Solutions  (Read 6721 times)
MadHacker
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November 28, 2011, 06:47:19 PM
 #21

I have made some solution for cooling VRMs on my 5970. First, after opening the card I removed original VRM thermal pads, which fell apart and seemed dried.  I replaced them with some 1mm thick, 6W/mK thermal conductiv pads from thermagon inc., but in result the VRM temps haven't improved.
Later I decided to experiment more and replace the thermal pads with copper plate and thermal grease.  I bought a 0.3mm thick copper plate and cut from it two strips to cover the VRM banks. Then, I put non conductive thermal grease (zm-stg2) on the surface of each VRM in the two banks (the VRM area on pcb would get dirty with grease) and covered it carefully with the copper strips. And also, I put thermal grease on the radiator side where vrm thermal pads had been sticked. Results:
Pros:
- vrm temps dropped about 10-15 degrees C and stayed below 120 degrees C (threshold temp) even with high core voltage like 1.15V,
- overclocking capability increased significantly – voltage could be risen much higher compared to pads
Cons:
- gpu temps increased about 5 degrees C, probably partly because of the better conductivity of heat from the vrm bank between gpu cores to the radiator which in result heats more when cooling gpus, but maybe also the original grease on gpus was better than my zm-stg2.
- I have read that producer uses thermal pads because during manufecturing the vrms could be soldered/placed at different hight and thermal pad could compensate this differences. It implies that the copper plate could not stick well to all vrms, or the one sticking out to much could get smashed maybe.
- quite risky - copper plate shouldn't touch any element...

Overall, I think that for bitcoin mining this modification could not be needed, because increasing voltage is not economical. And standard vrm cooling (with pads) is rather enough for economical (slight) oveclocking.

Remarks:
I also tried putting only thermal grease instead of pads and resulting vrm temps were better than with pads, so vrms are well tightened to radiator in my card at least.
The vrm bank with three vrms located between gpu cores heats more, in my card about 10 degrees C more, than the other bank (above fan), contrary to what this article says (I think, they misidentified the vrm banks): http://www.anandtech.com/show/3590 . But otherwise it's worth looking at, there are good pictures of the card.


That is also because the GPU die got less contact pressure or lack of contact due to the copper strip being too thick?
I dont know but i assumed you did use precision measurement of the thickness needed for VRM?

you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.
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November 28, 2011, 07:05:10 PM
 #22

I have made some solution for cooling VRMs on my 5970. First, after opening the card I removed original VRM thermal pads, which fell apart and seemed dried.  I replaced them with some 1mm thick, 6W/mK thermal conductiv pads from thermagon inc., but in result the VRM temps haven't improved.
Later I decided to experiment more and replace the thermal pads with copper plate and thermal grease.  I bought a 0.3mm thick copper plate and cut from it two strips to cover the VRM banks. Then, I put non conductive thermal grease (zm-stg2) on the surface of each VRM in the two banks (the VRM area on pcb would get dirty with grease) and covered it carefully with the copper strips. And also, I put thermal grease on the radiator side where vrm thermal pads had been sticked. Results:
Pros:
- vrm temps dropped about 10-15 degrees C and stayed below 120 degrees C (threshold temp) even with high core voltage like 1.15V,
- overclocking capability increased significantly – voltage could be risen much higher compared to pads
Cons:
- gpu temps increased about 5 degrees C, probably partly because of the better conductivity of heat from the vrm bank between gpu cores to the radiator which in result heats more when cooling gpus, but maybe also the original grease on gpus was better than my zm-stg2.
- I have read that producer uses thermal pads because during manufecturing the vrms could be soldered/placed at different hight and thermal pad could compensate this differences. It implies that the copper plate could not stick well to all vrms, or the one sticking out to much could get smashed maybe.
- quite risky - copper plate shouldn't touch any element...

Overall, I think that for bitcoin mining this modification could not be needed, because increasing voltage is not economical. And standard vrm cooling (with pads) is rather enough for economical (slight) oveclocking.

Remarks:
I also tried putting only thermal grease instead of pads and resulting vrm temps were better than with pads, so vrms are well tightened to radiator in my card at least.
The vrm bank with three vrms located between gpu cores heats more, in my card about 10 degrees C more, than the other bank (above fan), contrary to what this article says (I think, they misidentified the vrm banks): http://www.anandtech.com/show/3590 . But otherwise it's worth looking at, there are good pictures of the card.


That is also because the GPU die got less contact pressure or lack of contact due to the copper strip being too thick?
I dont know but i assumed you did use precision measurement of the thickness needed for VRM?


The gpu die has its own srews, so I think that the strips shouldn't lessen contact pressure significantly. But the elements located close to VRMs, like memory and CPLA-3-50( http://images.anandtech.com/reviews/video/ATI/5970OC/Card.jpg ) cooled with thermal pads could have significantly less contact. But those elements doesn't heat much during mining I believe.
I haven't done any precise measurement of the thickness, just estimated basing on the old, used VRM thermal pads (how much they were squeezed).
plastic.elastic
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November 28, 2011, 07:12:25 PM
 #23

I have made some solution for cooling VRMs on my 5970. First, after opening the card I removed original VRM thermal pads, which fell apart and seemed dried.  I replaced them with some 1mm thick, 6W/mK thermal conductiv pads from thermagon inc., but in result the VRM temps haven't improved.
Later I decided to experiment more and replace the thermal pads with copper plate and thermal grease.  I bought a 0.3mm thick copper plate and cut from it two strips to cover the VRM banks. Then, I put non conductive thermal grease (zm-stg2) on the surface of each VRM in the two banks (the VRM area on pcb would get dirty with grease) and covered it carefully with the copper strips. And also, I put thermal grease on the radiator side where vrm thermal pads had been sticked. Results:
Pros:
- vrm temps dropped about 10-15 degrees C and stayed below 120 degrees C (threshold temp) even with high core voltage like 1.15V,
- overclocking capability increased significantly – voltage could be risen much higher compared to pads
Cons:
- gpu temps increased about 5 degrees C, probably partly because of the better conductivity of heat from the vrm bank between gpu cores to the radiator which in result heats more when cooling gpus, but maybe also the original grease on gpus was better than my zm-stg2.
- I have read that producer uses thermal pads because during manufecturing the vrms could be soldered/placed at different hight and thermal pad could compensate this differences. It implies that the copper plate could not stick well to all vrms, or the one sticking out to much could get smashed maybe.
- quite risky - copper plate shouldn't touch any element...

Overall, I think that for bitcoin mining this modification could not be needed, because increasing voltage is not economical. And standard vrm cooling (with pads) is rather enough for economical (slight) oveclocking.

Remarks:
I also tried putting only thermal grease instead of pads and resulting vrm temps were better than with pads, so vrms are well tightened to radiator in my card at least.
The vrm bank with three vrms located between gpu cores heats more, in my card about 10 degrees C more, than the other bank (above fan), contrary to what this article says (I think, they misidentified the vrm banks): http://www.anandtech.com/show/3590 . But otherwise it's worth looking at, there are good pictures of the card.


That is also because the GPU die got less contact pressure or lack of contact due to the copper strip being too thick?
I dont know but i assumed you did use precision measurement of the thickness needed for VRM?


The gpu die has its own srews, so the plates shouldn't lessen contact pressure significantly. But the elements located close to VRMs, like memory and CPLA-3-50( http://images.anandtech.com/reviews/video/ATI/5970OC/Card.jpg ) cooled with thermal pads could have significantly less contact. But those elements doesn't heat much during mining I believe.
I haven't did any precise measurement of the thickness, just estimated basing on the old, used VRM thermal pads (how much they were squeezed).


More than likely its too thick then.



Tips gladly accepted: 1LPaxHPvpzN3FbaGBaZShov3EFafxJDG42
plastic.elastic
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November 28, 2011, 07:12:57 PM
 #24

I have made some solution for cooling VRMs on my 5970. First, after opening the card I removed original VRM thermal pads, which fell apart and seemed dried.  I replaced them with some 1mm thick, 6W/mK thermal conductiv pads from thermagon inc., but in result the VRM temps haven't improved.
Later I decided to experiment more and replace the thermal pads with copper plate and thermal grease.  I bought a 0.3mm thick copper plate and cut from it two strips to cover the VRM banks. Then, I put non conductive thermal grease (zm-stg2) on the surface of each VRM in the two banks (the VRM area on pcb would get dirty with grease) and covered it carefully with the copper strips. And also, I put thermal grease on the radiator side where vrm thermal pads had been sticked. Results:
Pros:
- vrm temps dropped about 10-15 degrees C and stayed below 120 degrees C (threshold temp) even with high core voltage like 1.15V,
- overclocking capability increased significantly – voltage could be risen much higher compared to pads
Cons:
- gpu temps increased about 5 degrees C, probably partly because of the better conductivity of heat from the vrm bank between gpu cores to the radiator which in result heats more when cooling gpus, but maybe also the original grease on gpus was better than my zm-stg2.
- I have read that producer uses thermal pads because during manufecturing the vrms could be soldered/placed at different hight and thermal pad could compensate this differences. It implies that the copper plate could not stick well to all vrms, or the one sticking out to much could get smashed maybe.
- quite risky - copper plate shouldn't touch any element...

Overall, I think that for bitcoin mining this modification could not be needed, because increasing voltage is not economical. And standard vrm cooling (with pads) is rather enough for economical (slight) oveclocking.

Remarks:
I also tried putting only thermal grease instead of pads and resulting vrm temps were better than with pads, so vrms are well tightened to radiator in my card at least.
The vrm bank with three vrms located between gpu cores heats more, in my card about 10 degrees C more, than the other bank (above fan), contrary to what this article says (I think, they misidentified the vrm banks): http://www.anandtech.com/show/3590 . But otherwise it's worth looking at, there are good pictures of the card.


That is also because the GPU die got less contact pressure or lack of contact due to the copper strip being too thick?
I dont know but i assumed you did use precision measurement of the thickness needed for VRM?

you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip

Tips gladly accepted: 1LPaxHPvpzN3FbaGBaZShov3EFafxJDG42
manet
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November 28, 2011, 08:23:56 PM
 #25



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.
MadHacker
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November 28, 2011, 08:33:59 PM
 #26



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

lapping the GPU core area could be a problem.
this change in thickness could be the reason for increates temperatures in the GPU.
perhaps you can apply more pressure to the GPU core to compensate.

my 6990 waterblocks has a problem with this in regards to contact with the VRM
I had to file off one of teh standoffs by a little bit to compensate.
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November 28, 2011, 09:09:04 PM
 #27

I checked my card temperature old logs and it seems, that I have exaggerated the gpu temperature increase, instead of 5 it was like 2-3 degrees C. Moreover, I noticed the increase some time after modification and the environment temperature changed so I am not precise here.
MadHacker
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November 28, 2011, 09:29:35 PM
 #28

I checked my card temperature old logs and it seems, that I have exaggerated the gpu temperature increase, instead of 5 it was like 2-3 degrees C. Moreover, I noticed the increase some time after modification and the environment temperature changed so I am not precise here.
well thats it...
you will just have to buy another video card and start all over...
this has to be precise...

ps: in case it was missed... this was sarcasm
plastic.elastic
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November 28, 2011, 10:04:00 PM
 #29



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

How did you lap the strip? Dont tell me you scrubbed fine sandpaper on it. Lapping requires much for precise and it has to be done on completely flat surface. What you did was "smoothing" the base which does not give perfect flat.

I suspect you did the same with the heatsink. You just made it worse.

 

Tips gladly accepted: 1LPaxHPvpzN3FbaGBaZShov3EFafxJDG42
MadHacker
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November 28, 2011, 10:48:00 PM
 #30



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

How did you lap the strip? Dont tell me you scrubbed fine sandpaper on it. Lapping requires much for precise and it has to be done on completely flat surface. What you did was "smoothing" the base which does not give perfect flat.

I suspect you did the same with the heatsink. You just made it worse.

 

prably held it in his fingers and rubbed it back and forth on a sheet of sanding paper... while at the same time trying not to wear of his fingers.
it can be done... not as easily as lapping a CPU but it can be done.
manet
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November 28, 2011, 11:22:14 PM
 #31



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

How did you lap the strip? Dont tell me you scrubbed fine sandpaper on it. Lapping requires much for precise and it has to be done on completely flat surface. What you did was "smoothing" the base which does not give perfect flat.

I suspect you did the same with the heatsink. You just made it worse.

 

prably held it in his fingers and rubbed it back and forth on a sheet of sanding paper... while at the same time trying not to wear of his fingers.
it can be done... not as easily as lapping a CPU but it can be done.

I cut some piece of sandpaper (about 3cm x 5cm) and was rubbing it around the heatsink gpu area with my finger Smiley. Yes, it was "smoothing" and I shouldn't do it this way because the resulting surface is not perfectly flat.
plastic.elastic
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November 29, 2011, 03:55:52 AM
 #32



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

How did you lap the strip? Dont tell me you scrubbed fine sandpaper on it. Lapping requires much for precise and it has to be done on completely flat surface. What you did was "smoothing" the base which does not give perfect flat.

I suspect you did the same with the heatsink. You just made it worse.

 

prably held it in his fingers and rubbed it back and forth on a sheet of sanding paper... while at the same time trying not to wear of his fingers.
it can be done... not as easily as lapping a CPU but it can be done.

How can you call that "done" when you bade it worse?

Last time i check human fingers arent flat; and to have the lapping done correctly, the sanding area must be larger than the base of the heatsink.

Tips gladly accepted: 1LPaxHPvpzN3FbaGBaZShov3EFafxJDG42
MadHacker
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November 29, 2011, 03:45:48 PM
 #33



you could always try lapping the copper strip trimming a little bit off it.
not much but just a little and then see if your GPU temp drops a little bit.


impossible, you have no grip


Actually I have been lapping the copper plate with super fine sandpaper (P1000, P1500) to make it more smooth. Also the cutting of the strips could be quite problematic because they should be really flat.
Moreover, I lapped also gpu core radiator area, maybe I haven't done this properly and only worsened gpu core temps.

How did you lap the strip? Dont tell me you scrubbed fine sandpaper on it. Lapping requires much for precise and it has to be done on completely flat surface. What you did was "smoothing" the base which does not give perfect flat.

I suspect you did the same with the heatsink. You just made it worse.

 

prably held it in his fingers and rubbed it back and forth on a sheet of sanding paper... while at the same time trying not to wear of his fingers.
it can be done... not as easily as lapping a CPU but it can be done.

How can you call that "done" when you bade it worse?

Last time i check human fingers arent flat; and to have the lapping done correctly, the sanding area must be larger than the base of the heatsink.

i was refering to the copper strip...
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