XFX Black Edition's and temps

Momo said:
... wouldnt the ideal solution be to use the stock base-plate for RAM / VRM cooling and your accelero for the GPU? Not sure if this is an option, or was, but i'm pretty sure it'd give you what you want / wanted.
Click to expand...

It was possible with the 5850s but the 5870s had a not-separating baseplate design. Anyway, those cards are off topic from this discussion but they really taught me a good lesson on why VRMs are so important and why keeping them cool is so important these days. Core and memory temperature are almost just afterthoughts to me now. The key to stability and over-clocking is really cooling VRMs with modern bleeding edge cards. They are your weakest link.
 
Porter_ said:
is that so? didn't know thermal imaging did anything more than surface temps, good to know. regardless this is my only means of testing since there are no sensors for AIDA64 etc. to report VRM temps. have a suggestion for a better way?
Click to expand...

Yes, that's why with FLIR, the police helicopters can "see" through your roof through infrared emissions to see if you are operating a pot-grow up in your house.

The best way with your gun is to see if you can manage to get a direct line of sight on an actual VRM module from the other end or through the side. I don't have a 7970 though so I don't know if this is possible with how the heatsink is attached.
 
Porter_ said:
the card exhausts in essentially all directions. i think of my case as a pressure boundary considering all of the in/out fans as a functioning system.
Click to expand...
Sounds like a bad design. Lots of potential for the cooler to take in hot air from it's own exhaust.
 
that i think the brute force approach of a larger heatsink and cramming a ton of air across it overcomes the potential risk you brought up.
 
XTF said:
I know. What's your point?
Click to expand...

You said it's a bad design. It's not. It's thermally more efficient to use large, slow moving fans to push air through large spaces than it is to use a small, high-RPM centrifugal fan to push air through a compact heatsink through tiny vents out the back of a card.

It's a design decision that must be taken into account with your cooling configuration. There's another thread that explains the advantages of a large heatsink with quiet axial fans versus that of a small heatsink cooled by a noisy blower fan. Thermally it is actually more efficient but in many cases, the recycled hot air going back into your system is not optimal unless your airflow setup as adequately implemented to take it into account.

Tudz said:
The reason the blower style is called the blower style is it has a blower style fan (centrifigul fan) which pushes the air tangentially to the fan blades, so the air is already heading in the direction of the back of the case, compared to a regular axial fan where the air has to turn a 90 degree corner after leaving the fan, which is not good since they typically have lower total and static pressures anyway.

Aside from that, exhausting out the rear may sound nice, but its really not efficient, which is why most aftermarket coolers stay away from it. Its pretty simple physics, the amount of cooling is proportional to how much cool air you can pass over the fins. If you force the air to travel the long distance over the fins and then out the tiny rear exhaust holes like a rear exhaust cooler, rather than through the fins and then out the ample exhaust region beneath the heatsink and into the case, you have to move the air at higher speeds and higher pressures, needing faster and louder fans, and fans more suited to the task (ie. centrifigul ones like in a blower cooler). Removing the hot air from the case by using a nice 120mm fan blowing through a 120mm exhaust is better than trying to force it through a tiny slot in the back of the card.
Click to expand...
 
Last edited:
Got a link to that thread?
You're right, big HSFs are good. But air doesn't magically move from case intake to GPU intake and from GPU exhaust to case exhaust.
Ideally you'd like to keep cold (intake) and hot (exhaust) air separated, but the internal exhaust design makes that difficult if not impossible.

BTW, the standard heatsink isn't small, is it?
 
Last edited:
XTF said:
Got a link to that thread?
You're right, big HSFs are good. But air doesn't magically move from case intake to GPU intake and from GPU exhaust to case exhaust.
Ideally you'd like to keep cold (intake) and hot (exhaust) air separated, but the internal exhaust design makes that difficult if not impossible.

BTW, the standard heatsink isn't small, is it?
Click to expand...

7970-pcb.jpg


That's the size of it. Not sure if it's less surface area than the other designs because it is taller since fans don't have to sit on top of it.

Air will still naturally rise by convection. Many cases these days have twin 120mm or larger exhausts on the top of the case these days and a spot on the side panel for a 120-200mm fan blowing onto the GPUs.

That setup when fully armed with a complement of quiet large axial fans will actually move significantly more heat than a small 60mm centrifugal blower fan forcing a fast current of air through a tiny slot in the back of a card.

Aside from everything I just said, I do still prefer blower cards because they tend to cool their power regulation circuitry (VRMs, etc.) much better than the cheaper (yes cheaper) big heatsinks with axial fans.
 
Thanks for the info guys.

I cancelled my order for XFX DD black edition.

I will be getting Sapphire reference $150 cheaper and overclocking it whatever I can, then one day later it's free for me to change the cooling to a custom cooling myself.

Cheers
 
Ghoststalker said:
Well I just installed the 4x120mm as an intake. I have a custom fan profile, temps maxed on the core at 80c. The fan on the BEDD was at about 82% at this speed, so that was definitely audible. On a positive note, I didn't crash the 15 minute test. Previously the only way I could pass was running the test with the fan at 100% and temps hit 84c. So I lost about 17% fan speed and 4-5c (temps just barely reached 80). This was also pulling air through a magnetic filter I have to reduce dust, which reduces CFM a little bit.

Worth noting that when I ran with my side panel completely off and the fan on the BEDD at 100% temps were at about 82c.

I will try again later with it setup as an exhaust from the side, though I don't know how that will work in my case. I currently have a 230mm front intake, 140mm exhaust, and 4x 120mm fans exhausting out the top through the H100 radiator. This will basically mean my only intake is the front, though I could reverse the 140mm in the back as well.
Click to expand...


Did you happen to capture your other temps at the time? Even if the temps on the gpu are similar the effect on the rest of the system could be significant.
Thank you very much for taking the time to work this out. Didn't mean to hijack the OPs thread, but it is relevant.
and oh yeah, they do still sell canned smoke. gonna have real fun on my next build, but thinking I am waiting for ivy bridge-e now, so April? bah!
 
Yeah they have 4 models. 2s card with reference cooling design, one of which is OC'd black edition, the other stock, and 2 card with Double D cooling design, one being black edition and one being stock.
 
I got the OC'ed Black (Non DD). Maxed sldiers in CCC with a voltage unlock in Afterburner to 1.17V. Runs perfectly with no issues in games. Heaven benchmark maxed out at 75C which is such a huge improvement over my GTX470 which was ran it at 89C.
 
Spare-Flair said:
Air will still naturally rise by convection.
Click to expand...
Except when there's airflow.
Many cases these days have twin 120mm or larger exhausts on the top of the case these days and a spot on the side panel for a 120-200mm fan blowing onto the GPUs.
Click to expand...
A side fan should help a lot. Might nearly be required. But what if there's no side fan? You might have one or two big exhaust fans in the top, but they might just suck air from the front intake without actually cooling your GPUs.

Suppose you use two of those cards, won't the second card take in the exhaust of the first one?
Aside from everything I just said, I do still prefer blower cards because they tend to cool their power regulation circuitry (VRMs, etc.) much better than the cheaper (yes cheaper) big heatsinks with axial fans.
Click to expand...
Hmm, is it the rule rather then the exception? I expected Asus & MSI to be smarter.
Why don't they connect the VRMs to the HSF?

Don't get me wrong, I love big HSFs but I'm just trying to understand the internal exhaust design.
 
uunut said:
Did you happen to capture your other temps at the time? Even if the temps on the gpu are similar the effect on the rest of the system could be significant.
Thank you very much for taking the time to work this out. Didn't mean to hijack the OPs thread, but it is relevant.
and oh yeah, they do still sell canned smoke. gonna have real fun on my next build, but thinking I am waiting for ivy bridge-e now, so April? bah!
Click to expand...

I didn't, but I can run the test again. I suspect my CPU temps will be fine since I use an H100 in a push/pull configuration. I didn't notice it audibly spinning up at all. For shits and giggles I bought a cheap infrared temperature gun from amazon. When it shows up next week I'll try to get some readings from the VRMs.
 
Last edited:
XTF said:
Hmm, is it the rule rather then the exception? I expected Asus & MSI to be smarter.
Why don't they connect the VRMs to the HSF?

Don't get me wrong, I love big HSFs but I'm just trying to understand the internal exhaust design.
Click to expand...

It seemed to be the rule with cards from the 4xxx to the 6xxx series which just had a tiny heatsink tacked onto the VRMs that was separate from the upper heatsink assembly. I just looked at the new XFX card and it looks like there is a heatplate covering the VRMs and the ram chips which is an improvement but there are no flat heatpipes from the plate into the main heatsink above which would help. The problem with slow moving fans is that the latent heat sits more in the fins of the aluminum heatsink above (which is fine for the core which is connected directly by heatpipes so heat will always transfer to some extent) but doesn't move off as fast from the entire assembly which has to move passively through adjoining metal which is what would need to happen for heat to transfer from the baseplate.

http://www.hardwareheaven.com/revie...-overclocked-the-xfx-r7970-black-edition.html
 
Last edited:
I m currently considering this model XFX:

XFX Double D FX-797A-TDBC

My real drive for this is the lifetime warranty. I intend on picking up another one in a couple months and I m just going to water block them. Since full blocks are available they will cool the VRAM, which will in turn solve this whole problem correct? That leaves me with a good warranty, 7970s, and a warranty not voided by waterblocking. Any objections tot his logic?
 
You must log in or register to reply here.
Back
Top