7970 VRM temps!?!?

[humbug]

My system shuts down when my vrams hit 125c.

Holy Crud!!!! its frighting to think you know that.... lol

 

[tommybhoy]

@op,

Hoping you come back and read this.

Are you using the AC Extreme 2 or the AC 7970 Extreme?

 

[Uncle Petey]

@Tommy and OP,

I took off the slim sinks on the VRM's and replaced them with the big one.
Here's a comparison of the big and small ones using thermal tape and thermal glue in my setup (The glue isn't permanent btw, it dries in a rubbery way like sealant).

VRM1 - Heaven Benchmark:

Tape w/Slim sinks: 64°C
Glue w/Slim sinks: 60°C

Tape w/Big sink: 71°C (requires additional securing with hot glue or something)
Glue w/Big sink: 57°C

Edit: forgot to mention that it's with a 7950 @1150/1425 1.131v. Obviously, a 7970 with higher clock/voltage will get higher temps.

 

[tommybhoy]

Thanks for the info, but what heatsinks were you using?

 

[Uncle Petey]

Ze Alpenfohn vuns of course

Slim = 4 of the narrow ones (Far left side in the product photo)
Big one = The big one that you're using.

I believe the slim ones fit the AC79 without needing to break out the tools

 

[Five.Stars]

Ze Alpenfohn vuns of course

Slim = 4 of the narrow ones (Far left side in the product photo)
Big one = The big one that you're using.

I believe the slim ones fit the AC79 without needing to break out the tools

So you would recommend replacing the VRM heatsinks supplied with the AC79 with the Alpnfohn 1's?

I would prefer not to have to take a dremel to my cooler if possible.

 

[tommybhoy]

Ah, the info's even better now, thanks again.

I have a 5870 Extreme cooler sitting screaming to be put onto the XFX 7950 DD(yes the warranty would be void) but the cpu holes don't line up with the bracket.

However, if I can get conformation that the Extreme 2 fits, then I'l buy the bracket from it direct from AC as it's the exact same cooler.

Either that or just use some cable ties instead to hold the Extreme in place.

It's a high Asic, so maybe I won't need the big chunky Alpenfohn vrm sink as I have plenty of the other ones left.

 

[Uncle Petey]

So you would recommend replacing the VRM heatsinks supplied with the AC79 with the Alpnfohn 1's?

I would prefer not to have to take a dremel to my cooler if possible.

I'm saying it can't hurt to try
They are definitely higher quality as Tommy has shown with his mod, so you should get better results.

If you don't mind using the included glue, you'll get the best performance.
Cleaning it off the board may be a slight pita at some point though. More awkward than anything due to the VRM location and all it's nooks and crannies.

Ah, the info's even better now, thanks again.

I have a 5870 Extreme cooler sitting screaming to be put onto the XFX 7950 DD(yes the warranty would be void) but the cpu holes don't line up with the bracket.

However, if I can get conformation that the Extreme 2 fits, then I'l buy the bracket from it direct from AC as it's the exact same cooler.

Either that or just use some cable ties instead to hold the Extreme in place.

It's a high Asic, so maybe I won't need the big chunky Alpenfohn vrm sink as I have plenty of the other ones left.

Apart from the bracket, the contact plate isn't compatible with 7xxx afaik due to not having the raised 'diamond' bit. There is a copper shim available somewhere iirc, but it does compromise temps a little.

 

[tommybhoy]

Apart from the bracket, the contact plate isn't compatible with 7xxx afaik due to not having the raised 'diamond' bit. There is a copper shim available somewhere iirc, but it does compromise temps a little.

Yes I bought 2 EK shims ages ago before I even got any 79's just in case, although I might just convince myself to try and take the guard off since I'm going to blooter the warranty anyway.

Poor show XFX with the screw stickers-although there's a chance they can come off without touching the screw head with a screwdriver.

 

[Uncle Petey]

Yeah sorry, I should've figured you'd know that already

Looking at this article, the shim costs over 10°C. Would that be better than the stock cooler? Quieter I'll bet.

Tbh, I've found that getting the hot air out of there is the key. Just blowing air up through the heatsink and onto the VRMs isn't enough by itself. Well, it's ok but doesn't give optimal results.
Having side fans directly exhausting from the card plus a fan on the HDD bays blowing directly at the VRM's drops 10°C+ vs just using bottom fans.
I'm not suggesting that anyone should go down the same path as me though and it'd be a bit awkward to do on an Accelero

 

[BrianB]

My Acclero set to 50% with the stock VRM heatspreader installed doesn't seem to let my VRM's go much over 80 when overclocked. I only seem to get artifacts at high voltage rather than high vrm temps. I used Akasa Thermal Tape to attach my vram sinks. It helps to have some cool intake going towards the card and having some good exhaust. My core doesn't really go over 43c most days.

I have been able to push my vrms to over 105C before, but that was using something like Kombustor lol with 1300/1600/1300mv.

 

[tommybhoy]

Yeah sorry, I should've figured you'd know that already

Looking at this article, the shim costs over 10°C. Would that be better than the stock cooler? Quieter I'll bet.

Even though it won't cool as good as the proper 79 heatsink, it should still lower the temps, as when I add just a little extra volts, the core temp goes through the roof on the DD, the cooler just can't cope.

Tbh, I've found that getting the hot air out of there is the key. Just blowing air up through the heatsink and onto the VRMs isn't enough by itself. Well, it's ok but doesn't give optimal results.
Having side fans directly exhausting from the card plus a fan on the HDD bays blowing directly at the VRM's drops 10°C+ vs just using bottom fans.
I'm not suggesting that anyone should go down the same path as me though and it'd be a bit awkward to do on an Accelero

They really do need a decent amount of cool air, it helps an awful lot with overclocking.

I have a P280 with 2 intake fans on the front with another 2 on the HD tray sucking loads of air through the gpu's although the top one doesn't get as much air as the bottom card, it does drop the temps down considerably when I turn the dials up on the controller.

 

[Uncle Petey]

Having seen MOOGLEYS pic of the heatsink design, I'd be desperate to get that thing replaced too
Can't believe there's no airflow through the sink to the VRM's on that card.

Not sure what you mean by 2 fans on the HD tray. Any chance of a pic?

Here's what I'm working with:

Spoiler

Ignore the cardboard/gaffa tape shroud. It's a test placeholder for something made from black acrylic hopefully.

The side exhausts are more critical than the front intake. Side panel mods needed to take full advantage of them though. I gots plans
Definitely not for everyone... Not sure how they'd work with an AC79.

 

[kamz]

Uncle what did you use to stick the ram sinks and that big vrm block, i tried using thermal tape but small sinks tend to drop off, and i got no chance on the big block, hoping for something none permanent

 

[Uncle Petey]

For the RAM sinks, I spread thermal paste on the bottom and wiped away a small bit on two opposite corners. I then put a tiny drop of superglue on those two corners and drew away any excess with a tissue.
Simple, clean and non-permanent. They'll just pop off when you need to remove them or you could slide a razor blade underneath if you want to be a bit more careful.

I used the supplied Alpenfohn thermal glue to attach the big one. Thermal tape'll never hold that brute I tried it previously and even had to use a blob from a glue gun at each end and it still wasn't right.
EDIT: I also used the glue for the lone slim sink on the VRM at the far right.

Thermal tape should hold the smaller ones ok. It did for me when I used 4 of the slim sinks on the VRMs.

 

[tommybhoy]

I'm not at my PC, I'm at work but I changed your pick to more or less what it's like:

Spoiler

Just ordered an Extreme 2 bracket and screws from AC in Hong Kong for my spare 5870 Extreme sitting lonely in a box, so I'm playing the waiting game now.

@kamz, for the tape to stick and it will(bar the big vrm in pete's pics) you need to rub the vrams with a pencil rubber, then do it again and again, there is residue that's left over from the stock pads that needs to be cleaned properly.

 

[Uncle Petey]

Oh, I get you now. Nice 'shop skills ')

Should be interesting to see what results you get since you can compare directly to the official AC 79xx.

 

[Devrij]

Having seen MOOGLEYS pic of the heatsink design, I'd be desperate to get that thing replaced too
Can't believe there's no airflow through the sink to the VRM's on that card.

Not sure what you mean by 2 fans on the HD tray. Any chance of a pic?

Here's what I'm working with:

Spoiler

Ignore the cardboard/gaffa tape shroud. It's a test placeholder for something made from black acrylic hopefully.

The side exhausts are more critical than the front intake. Side panel mods needed to take full advantage of them though. I gots plans
Definitely not for everyone... Not sure how they'd work with an AC79.

How have you mounted those side fans? I'd be interested in something like that. Most of my gfx heat seems to get exhausted out the top rear of my case, so I'd rather it went out the side instead of into my cpu heatsink. My side panel is made for a 200mm fan though, which would foul my cpu heatsink.

 

[Uncle Petey]

You could buy an Alpenfohn Peter or just get one of these

Not sure what case you're using, but my 500R has a 200mm side panel vent (fan removed) and it's ok for the moment although gpu/vrm temps are slightly higher than they would be with the side panel off or with proper venting.
There are plans in motion to deal with it in an asthetically pleasing and very functional way. Stay tuned

EDIT: I would also add that using the bracket means that the fans are right next to the card. I believe this makes a much bigger difference compared to normal case-mounted side fans unless you fashion some sort of ducting.

Spoiler

In my old case, I had it set up like this with a 230mm hole cut in the side.

 

[Locky]

Mine don't break 30 degrees C