2x 7970 Few questions

[BBQKorv]

Open air case and a big boxfan is needed for good temps. Something like this: http://www.stomped.me/pics/100_0253.JPG

That screenshot was taken just a few seconds after launching cgminer, values will get more accurate over time and those rejects came only in the very beginning.

[drlukacs]

Open air case and a big boxfan is needed for good temps. Something like this: http://www.stomped.me/pics/100_0253.JPG

Where did you get the frame that the parts are attached to?

[pontiacg5]

4 gigabyte 7970 GHz editions, OC to 1150 and 1150 mem. All average out about 700MH/s.

They'd run cooler if I could figure out these riser cables. These are all sandwiched on the mobo with a box fan running full tilt.

Running anything higher than 1150 is crazy unstable to me, even with only one card in the board running at 70's. 

[drlukacs]

4 gigabyte 7970 GHz editions, OC to 1150 and 1150 mem. All average out about 700MH/s.

Why do you not lower the memory to 600 Mhz?

[pontiacg5]

I don't think it will actually take anything less than 1000 for memory, it reverts back to 1500 every time for me.

Matched to the clock seems to work best for me.

[drlukacs]

I don't think it will actually take anything less than 1000 for memory, it reverts back to 1500 every time for me.

Did you look into altering the bios?

[pontiacg5]

Of the cards? I guess I could, but would I really see any benefit besides ruining my warranty?

[miningdude]

pontiacg5, you're gonna burn up your cards with those temps. Youch! I like to keep the gpu's in my mining rigs lower than 75. I use box fans (they move the most air for mere pennies worth of electricity each day). You can check out my quad 7970 litecoin mining rig build here. Also, I'm assuming you're using risers and spacing out those cards for maximum airflow?

[Sophokles]

Open air case and a big boxfan is needed for good temps. Something like this: http://www.stomped.me/pics/100_0253.JPG

That screenshot was taken just a few seconds after launching cgminer, values will get more accurate over time and those rejects came only in the very beginning.

Nice setup! What are those? 7970 or 7950? scrypt or SHA256 mining? No powered risers, right?


I have a 4x 7970 system, mining LTC, considering plugging a fifth 7970 in there. PSU is 1500W. Will report back, hope I don't fry the mobo or something...

[pontiacg5]

pontiacg5, you're gonna burn up your cards with those temps. Youch! I like to keep the gpu's in my mining rigs lower than 75. I use box fans (they move the most air for mere pennies worth of electricity each day). You can check out my quad 7970 litecoin mining rig build here. Also, I'm assuming you're using risers and spacing out those cards for maximum airflow?

Hey! I've already posted on your blog! Fancy seeing you here 

Nope, no risers. I've got a quad crossfire board so they all fit. That's why the temps are so high, the cards are sandwiched!! Crazy box fan pushing on them all now, but still won't get less than 90c.

I tried using 8x to 16x risers, they didn't work. Tried wrapping them in aluminum tape, didn't work. My mobo has external power for the PCIe rails, so I don't think I'd need powered risers but that's all I haven't tried yet.

I picked 8x risers because that's what all 4 of my cards run at, 8x. I think 1x might help, maybe?

[vonross2012]

Open air case and a big boxfan is needed for good temps. Something like this: http://www.stomped.me/pics/100_0253.JPG

That screenshot was taken just a few seconds after launching cgminer, values will get more accurate over time and those rejects came only in the very beginning.

Where did you get the square tubing and junction pieces?

[MrBilling]

pontiacg5, you're gonna burn up your cards with those temps. Youch! I like to keep the gpu's in my mining rigs lower than 75. I use box fans (they move the most air for mere pennies worth of electricity each day). You can check out my quad 7970 litecoin mining rig build here. Also, I'm assuming you're using risers and spacing out those cards for maximum airflow?

Hey! I've already posted on your blog! Fancy seeing you here 

Nope, no risers. I've got a quad crossfire board so they all fit. That's why the temps are so high, the cards are sandwiched!! Crazy box fan pushing on them all now, but still won't get less than 90c.

I tried using 8x to 16x risers, they didn't work. Tried wrapping them in aluminum tape, didn't work. My mobo has external power for the PCIe rails, so I don't think I'd need powered risers but that's all I haven't tried yet.

I picked 8x risers because that's what all 4 of my cards run at, 8x. I think 1x might help, maybe?

I don't think people realize how hot 90 C is.


On my Sapphire 7950's there is a black part right under the two red stripes.  This piece is metal, not plastic.


When these cards get up to 80 C if you touch the metal piece it will burn you.  You will not be able to keep your finger on it for more than 2-3 seconds.



90 C is HOT!

[Eich]

194 F

[silicont]

drlukacs:

7970s have a 150 difference max between the engine and the memory.  So if your engine is at 1150, you can set your memory to 1000, but not 950.  At least on the gigabyte 7970s I have using cgminer.

[drlukacs]

drlukacs:

7970s have a 150 difference max between the engine and the memory.  So if your engine is at 1150, you can set your memory to 1000, but not 950.  At least on the gigabyte 7970s I have using cgminer.

Why do you not use a modded BIOS?

[KS]

4 gigabyte 7970 GHz editions, OC to 1150 and 1150 mem. All average out about 700MH/s.

They'd run cooler if I could figure out these riser cables. These are all sandwiched on the mobo with a box fan running full tilt.

Running anything higher than 1150 is crazy unstable to me, even with only one card in the board running at 70's. 

I think I remember reading somewhere that 90°C is the limit those chips are designed to tolerate, and I don't suppose that means 24/7.

[silicont]

Why do you not use a modded BIOS?

I'm inspired to, now!  Thanks.

[drlukacs]

Why do you not use a modded BIOS?

I'm inspired to, now!  Thanks.

Need help with modding your BIOS?

[r3v07ut10n]

what script settings are you guys running? i only get 670

[silicont]

drlukacs, I was going to start searching, as I know I've seen the instructions out here, but if you have a link or have some hints, I'd appreciate them.  I have Gigabyte GV-R797OC-3GD.  Thanks.