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Dual 7950s, blower vs open cooler

Skurge

Skurge

Diamond Member
So, after seeing what the 780 cost, I've decided to get dual 7950s instead.

My rig is in the sig below. My case isn't known for its cooling abilities and I had issues keeping my 6990 cool, but I also prefer a quiet case.

So I don't know if I should get 7950s that have the reference cooler or Something like the Windforce 3x or Vapor-X coolers cause I don't know if I my case will be able to handle all that heat.

I wanted to know what setup would put out more heat. 2x 7950 or a single 6990. And then also noise. I am currently running a reference 5850 and the noise isn't too bad, I wish it was quiter, but It's bearable. How does that compare to a reference 7950?
 
Alas,

HIS doesn't have a distributor in Namibia. So my options are MSI, Asus, Gigabyte and Sapphire. Although the Ice Q would work perfectly, I don't see any similar cards from anyone else.
 
3DVagabond said:
What about the HIS Ice Q? Your mobo has the spacing for it (three slots).
Click to expand...

Do keep in mind the the VRMs on this model are cooled entirely by an add-on aluminum strip heatsink that is for all intents and purposes completely passively cooled since it's neither attached to the main heatsink nor does it get a fan blowing onto it.

My card can only do 1050 mhz core@1.3v 1575 mhz memory@1.7v.

This is entirely because of the lack of cooling of the VRMs.

If I found a way to cool the VRMs better, I could get those clocks at much lower set voltages since the VRMs would be able to far better deal with VDroop.
 
Skurge said:
I can get that, just a little worried about the noise. Not sure how it compares to the 5850
Click to expand...

The problem is the only non-reference blower that's better than the reference blower is the HIS IceQ, so that specific Sapphire card is the best you're going to get.

I know it's tempting to run 2x 7950 with open coolers but I know from personal experience that its a very bad idea, and I have probably the best airflow case possible.

A bad airflow case using 2x 7950 Open Coolers will definitely be a problem.
 
You could get a reference model and then do the "red mod" on both. I keep toying with the idea but I still haven't tried it.
 
how do you guys know whether a reference blower card cools better than one with 2 fans on top? is there any charts somewhere to look at?
 
Communism said:
The problem is the only non-reference blower that's better than the reference blower is the HIS IceQ, so that specific Sapphire card is the best you're going to get.

I know it's tempting to run 2x 7950 with open coolers but I know from personal experience that its a very bad idea, and I have probably the best airflow case possible.

A bad airflow case using 2x 7950 Open Coolers will definitely be a problem.
Click to expand...

Yeah, I know I had that issue with the 6990. I guess I will just have to to turn my volume up a little higher.

Should be here next week.
 
Communism said:
Do keep in mind the the VRMs on this model are cooled entirely by an add-on aluminum strip heatsink that is for all intents and purposes completely passively cooled since it's neither attached to the main heatsink nor does it get a fan blowing onto it.

My card can only do 1050 mhz core@1.3v 1575 mhz memory@1.7v.

This is entirely because of the lack of cooling of the VRMs.

If I found a way to cool the VRMs better, I could get those clocks at much lower set voltages since the VRMs would be able to far better deal with VDroop.
Click to expand...

Why don't you try installing Fujipoly thermal pads? They help drop my vrms temps buy 10-20c.
 
Skurge said:
So, after seeing what the 780 cost, I've decided to get dual 7950s instead.

My rig is in the sig below. My case isn't known for its cooling abilities and I had issues keeping my 6990 cool, but I also prefer a quiet case.

So I don't know if I should get 7950s that have the reference cooler or Something like the Windforce 3x or Vapor-X coolers cause I don't know if I my case will be able to handle all that heat.

I wanted to know what setup would put out more heat. 2x 7950 or a single 6990. And then also noise. I am currently running a reference 5850 and the noise isn't too bad, I wish it was quiter, but It's bearable. How does that compare to a reference 7950?
Click to expand...

You said you case already struggled in the past with cooling GPUs, so I would just play it safe and get at least one reference-style blower card and one open-air. Or two reference style blowers if you really want to. If you really want to, you can also go water-cooled. I would not worry about the noise even if you decide on 2x air-cooled because it only gets bad if you overclock/overvolt significantly, and even then you can use headphones.
 
Communism said:
And connect them to what?

The VRMs are literally only connected to a small free floating heatsink about 3-4 centimeters at least away from the closest heatsink that's actually connected to the airflow path.

http://www.guru3d.com/miraserver/images/2012/7950-his-iceq/IMG_6544.jpg
Click to expand...

It's hard to see In that picture, but is the vrm heatsink part of the plate assembly that wraps around the far right side of the pcb? Do screws attached it to the PCB? If it's free floating only then I assume it's attached to the vrms by the way of thermal compound or thermal tape, not screws.

EDIT: Uploaded better pic

HIS_HD7950_IceQ_Turbo_3GB_Cooler_Removed.jpg


I see now. Yes you can use the thermal pads under the heatsink. It looks like the heastsink/plate is attached to the pcb using screws. Just unscrew the plate and remove the stock thermal pad and replace them with some of the Fujipoly of the same thickness. Should be 1mm. The fan also pulls air off of the pcb right where the vrms are, so you have some air movement.

http://www.frozencpu.com/products/1...x_15_x_10_-_Thermal_Conductivity_110_WmK.html
 
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I always have preferred the blower type because it doesn't blow hot air back into the case. I prefer quiet cases so none of my cases have the huge exhaust volume needed to handle -non-blower fans.
 
Face2Face said:
It's hard to see In that picture, but is the vrm heatsink part of the plate assembly that wraps around the far right side of the pcb? Do screws attached it to the PCB? If it's free floating only then I assume it's attached to the vrms by the way of thermal compound or thermal tape, not screws.

EDIT: Uploaded better pic

HIS_HD7950_IceQ_Turbo_3GB_Cooler_Removed.jpg


I see now. Yes you can use the thermal pads under the heatsink. It looks like the heastsink/plate is attached to the pcb using screws. Just unscrew the plate and remove the stock thermal pad and replace them with some of the Fujipoly of the same thickness. Should be 1mm. The fan also pulls air off of the pcb right where the vrms are, so you have some air movement.

http://www.frozencpu.com/products/1...x_15_x_10_-_Thermal_Conductivity_110_WmK.html
Click to expand...

I guess next time I try to fiddle with my gfx cards I'll try that.

Absolutely pessimistic as to any benefit though, as the airflow to the small free floating heatsink assembly is absolutely trash compared to any old non-blower will provide because of the orientation of the stream.

My card differs from the card in the review it would seem, as the one in the review has the VRM heatsink being part of the casting of the brace. Mine is free-floating last I checked with an oily layer on top of the heatsink array for some reason.
 
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Communism said:
I guess next time I try to fiddle with my gfx cards I'll try that.

Absolutely pessimistic as to any benefit though, as the airflow to the small free floating heatsink assembly is absolutely trash compared to any old non-blower will provide because of the orientation of the stream.
Click to expand...

I understand 😀

I will say the heatsink surface area on your card is much larger than my MSI card. I had to add some heatsinks on top of the plate using thermal tape to add more surface area for the heat to dissipate through. I do have more air movement, but you have more surface area. If I had to guess I would say you would see a drop of 10c on the vrms temps under load, maybe more?

Here is a pic of my setup without the cooler. This has allowed me to game with 1250 on the core with vrm temps below 90c.

IMAG0423_zps1f9639fa.jpg
 
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blastingcap said:
You said you case already struggled in the past with cooling GPUs, so I would just play it safe and get at least one reference-style blower card and one open-air. Or two reference style blowers if you really want to. If you really want to, you can also go water-cooled. I would not worry about the noise even if you decide on 2x air-cooled because it only gets bad if you overclock/overvolt significantly, and even then you can use headphones.
Click to expand...

Ok then, gonna pull the trigger on those sapphire blower cards.
 
Face2Face said:
I understand 😀

I will say the heatsink surface area on your card is much larger than my MSI card. I had to add some heatsinks on top of the plate using thermal tape to add more surface area for the heat to dissipate through. I do have more air movement, but you have more surface area. If I had to guess I would say you would see a drop of 10c on the vrms temps under load, maybe more?

Here is a pic of my setup without the cooler. This has allowed me to game with 1250 on the core with vrm temps below 90c.

IMAG0423_zps1f9639fa.jpg
Click to expand...

I can't really give you any temps since the I2C shows 24-25C at all times for VRM1 and VRM2, most likely either because they never actually put any leads for them or they just put them onto the pcb any which where and then never calibrated them <.< (Since that temp is actually lower than the ambient temperature when I tested).

I will definitely try it next time I fiddle with it though, but I will probably need to somehow stuff a slim 80-92mm fan facing up directly on the VRM heatsink to try to increase the airflow.

The huge problem with the HIS IceQ's VRM array is that from what I can tell, its got 9 VRMs, but the 7 VRMs that aren't dedicated to the VRAM are all stuffed under that strip with absolutely inadequete VRM cooling.

That's probably why the card functions just fine drawing 160-170 A @ 1.2-1.24v measured from GPU core and 20-30 A @ 1.7v measured from the VRAM.

Calculate that out and its 192-210.8W !!! from the GPU core and 34-51 W !!! from the VRAM and that's before adding the probably 5-15W drawn by that huge blower.

Also, I'd wager the VRM heatsink surface area is approximately the same between that TF3 and the IceQ because the IceQ's "grooves" are only about 1mm deep, while the TF3's look to be a centimeter or so tall, which also would benefit catching the airflow just because of the shape.
 
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This is the stock vrm/memory plate for the MSI TF3 = sucks

900x900px-LL-d8b8e933_20130207-IMG_0032.jpeg


I added the heatsinks you see in the picture in the above post.

Maybe you can add a fan somehow on the end of the card blowing air right where the fan pulls air from?
 
Face2Face said:
This is the stock vrm/memory plate for the MSI TF3 = sucks

900x900px-LL-d8b8e933_20130207-IMG_0032.jpeg


I added the heatsinks you see in the picture in the above post.

Maybe you can add a fan somehow on the end of the card blowing air right where the fan pulls air from?
Click to expand...

Ah, did not realize that. That makes sense.

Yes I plan on doing the fan thing, just need to look for a fan that's slim, 92mm, and quiet-ish and a decent way to mount it other than superglue.
 
Communism said:
Ah, did not realize that. That makes sense.

Yes I plan on doing the fan thing, just need to look for a fan that's slim, 92mm, and quiet-ish and a decent way to mount it other than superglue.
Click to expand...

😀 Isn't there a fan mount on the back/ or side of the HDD cage on the Antec 1100? Would that be sufficient enough?
 
Face2Face said:
😀 Isn't there a fan mount on the back/ or side of the HDD cage on the Antec 1100? Would that be sufficient enough?
Click to expand...

Not really, no natural airflow pattern will reach those heatsinks in the way they are placed. They are baffled by the brace as well as have a solid object blocking the back of them as well as having an updraft stealing away what air happens to go to it o.o;;

I have also found that those two fan mounts are the most useless fan mounts in the whole system, since any non-blower card will be pushing air at the front of the case, and having a fan just inches away from it pushing that air back is just a bad idea.

The fans put there also have the horrible effect that Gigabyte's current Windforce 3 on their 7950/7970 have in that they just suck in circles.

I think the only real use of those 2 fan mounts is for a radiator which would not allow that because it would block most of the recirculation as well as not have to deal with cards blowing directly onto them.
 
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