Topic: [LTC] 3x 4x 7950 need help (Read 1500 times)

Sorry - talking cross purposes...

I said i had the issue with my 7970s (which is all i run nowadays), didn't notice you asked about 7950's. nedlees to say, those stats are from 4x 7970s in each rig.

You are not talking about 7950s, I have never seen 750kh/s per card
Maybe you have 5 cards

This is mine, it's rock solid but not I am just at 600kh

current averages:

Rig 1 - 3.022Mh/s
Rig 2 - 3.019Mh/s
Rig 3 - 2.996Mh/s - Hmmm need to fiddle with this one me thinks.
Rig 4 - 3.004Mh/s

I have rebuilt my rig with a msiz77a-g54, 4 cards running at 605/605/610/580, WU=92%
It seems stable but I think I need at least 1 power riser to be sure

Nutnut what's you stable hash for 4x7950?

I had exactly the same issue when i upgraded from 2 windforce 7970 to 4 on a GA-990FXA-UD3. Was losing about 70Khs per card. Bizarrely, once i removed the additional cards i was still 70Khs down. After pulling my hair out I totally blew away the os (Win7) and rebuilt with all 4 cards in... Been fine ever since. Have no idea why! Maybe worth a shot...

I am trying to set up 4x7950

gigabyte windforce v2 flashed bios for 1.090v
13.3 beta
cgminer 2.11.3
w7 64bit, 8gb in a sigle stick
pci risers x1 to x1 to the cards

At the moment I have 3x on a cheap gigabyte mobo which doesn't recognize the 4th card (shorting not attempted)
I bought an MSI Z77A-G45 and I will try it tonight to see if the mobo is the problem, I hope so 

I use an xfx 1250w gold, 3x at 1000/1250/+20% run stable at 750w from wall

I can run stable each card individually to 660kh with 1125(55)/1450/+20% I 19 tc 16384, with or without risers.

When I put 3 together I cannot go over 595-605kh each, (600/550/600 reported on pool) with 1000/1250/+20% temps about 65-72c with fan 60%

At the moment I run guiminer with this cmd:
cgminer.exe --scrypt -u x-p-x o x --gpu-platform 0 -d 0 -w 256 -v 1 -I 20 -g 1 -l 1 -T  --thread-concurrency 21712
cgminer.exe --scrypt -u x-p-x o x --gpu-platform 0 -d 1 -w 256 -v 1 -I 20 -g 1 -l 1 -T  --thread-concurrency 21712
cgminer.exe --scrypt -u x-p-x o x --gpu-platform 0 -d 2 -w 256 -v 1 -I 20 -g 1 -l 1 -T  --thread-concurrency 21712

I know a lot of people can keep 1 card at 660kh stable, I also can but what about 3 or 4 cards?

What's your hashrate/clock/mem with 3 or 4 7950?

Why do I get mixed results between 1 card and multiple cards? is it the mobo which cannot keep it ? or maybe the psu (I doubt this)?

I want to squeeze every single hash from these cards, I know 1750-1800kh is good for 3 cards but I am more looking at 650kh each card.
So, is it possible?

Thanks