My failed 7870 XT Mod

[silkstone]

no no no.
the chips is more sensitive. vrms are typical mosfets. they use pads because vrms are not made very strictly, so they are of varying lengths. also soldering may lead to little bit different height.

i used an ample amount of TIM on something, and it worked, better than the pads. was a long time ago, so i cant remember what it was.

and anyways, most of them are rated for around 115C.

I'm not really willing to risk damaging the card to try direct contact with the aluminium sink at the moment. As the VRMs are only hitting 80 C, I imagine they are pretty safe. The point of the new fans was to try and reduce noise and help temps, but the VRMs start to go over 100 with the fans I tried. I believe the thermal paste I have is non conductive, but I don't feel that comfortable gooping it all over the PCB. If I had a card I could replace, then I would.

I like the idea of putting a heat sink on the back of the pcb, but making sure it stays there would be an issue.

The 92mm fan is something I may try at a later date, but the main problem is that the fan housing is circular and blue; it won't work well with the other 2 fans. I may be able to get some stuff from the US come December, I'll have a look around at what I can find.

 

[Nordic]

You only have one card right? I have two of them. When I have the cards in crossfire, while under load the fans can get up to 80% and are loud. When I have either of my two cards in single card configeration they barely get up to 60% fan speed and are not that loud. Anything past 60% just gets really loud.

Maybe the problem is not the fans on the heatsink but the airflow of the case.

 

[fkr]

look

http://www.overclock.net/t/1373543/official-7870-tahiti-le-xt-owners-club

this is a great resource for our cards and an active community for all things tahiti LE. there are some good fan recommendation that have good static pressure and also many users who have done this mod with allot of success.

I will probably not be back this way but I wanted to help another tahiti le user and do not fret your temps can be very much improved

 

[silkstone]

You only have one card right? I have two of them. When I have the cards in crossfire, while under load the fans can get up to 80% and are loud. When I have either of my two cards in single card configeration they barely get up to 60% fan speed and are not that loud. Anything past 60% just gets really loud.

Maybe the problem is not the fans on the heatsink but the airflow of the case.

Yea, only the one card and I use a custom fan profile to keep the temps under 80 C. The airflow in the case is pretty good. I have 6 x 120mm fans, 1 x 140mm and 1 x 200mm fan an various configurations. The good thing about the HAF series of case is the airflow

When playing FC3, the fan spins up to 80% or so. It's not as noisy as at 100%, but is definitely noticeable. I can live with the noise, I wanted a mini project for my Sunday afternoon so I'm not too fussed that it failed, I'm just a little annoyed at myself for stupidly trying to remove a fan header with piers.
I'll read through the thread above and see how other people are modding theirs.

 

[ne6togadno]

Yea, only the one card and I use a custom fan profile to keep the temps under 80 C. The airflow in the case is pretty good. I have 6 x 120mm fans, 1 x 140mm and 1 x 200mm fan an various configurations. The good thing about the HAF series of case is the airflow

When playing FC3, the fan spins up to 80% or so. It's not as noisy as at 100%, but is definitely noticeable. I can live with the noise, I wanted a mini project for my Sunday afternoon so I'm not too fussed that it failed, I'm just a little annoyed at myself for stupidly trying to remove a fan header with piers.
I'll read through the thread above and see how other people are modding theirs.

have a look on this
take one of those SK 81 / 100 SA heatsinks and make horizontal cut on the sink (heatsink should be oriented as at the photo).
use original heatsink to duplicate holes for bolts to new one.
if gpu cooler doesnt fit cut top ends of ribs of the new heatsinkbut just enough cooler to fit.
try to place new sink with different pads and tim till you get best heat transfer. you may also want to replace standard heatsink screws with spring screws.
if fans you have still cant handle vrm temps try one of those
EVERCOOL F-EC9225HH12BP 92x92x25mm High Speed Do...
EVERCOOL RVF-2F Ever Lubricate Replacement Fan for...

 

[de.das.dude]

if you can find some piece of spare copper, duplicate the dimensions and design of the current heatsink. that would be great!

 

[ne6togadno]

if you can find some piece of spare copper, duplicate the dimensions and design of the current heatsink. that would be great!

there are avilable premade copper heatsinks but they are too short 2-3 has to be used to cover all vrms. this will require custom bracket and material with good elastic capabilities to be used for it. i think sk81/100sa mod will be easyer for crafting.

ps may be locking bracket from old cpu cooler like this could be moded and used together with enzotech's rads. this solution wont need spring bolts.

 

[silkstone]

Thanks for the input, but in all honesty, the temps aren't worth the effort. I was going for something cheap and quick that I could do on a Sunday afternoon.

They are both excellent ideas, and if I had more time, I would try them. I especially like the idea of milling my own heatsink out of copper.

The gpu temp is sitting at 71 C max and the VRM has now settled at ~75 C.
The card does still get very hot to the touch, and so I am thinking of re-purposing the fans I got to cool the back of the card somehow; I think I will have to do something ghetto.

 

[AsRock]

Looking at the cooler and the crappy heatsink on the VRMs is the issue. The cooler looks like it blocks most of the air flow which is why they made it a single fan so the air be pushed across the PCB.

Might look some what ugly try fitting a fan on the left side to help pull air though passed the VRM's.

 

[Beertintedgoggles]

One of the easiest things you can try which should lower the temps maybe 3-5 C would be to replace the white plastic posts and springs that attach the VRM heatsinks with some metal bolts, nuts and plastic washer to put more mounting pressure which will help compress the thermal pads better. I also like to put a dab of TIM on the VRMs and the heatsink (essentially both sides of the thermal pads). It might sound like you will be insulating them more that way but give it a shot, you will be surprised.