Problem mining litecoin + multiple graphics cards and cgminer(Bitcoin is fine)

[The Mafia]

Hi Everyone

I am having a really annoying problem with litecoin mining.

I have a PC with these specs (And other variants to test hardware):

Core2Duo 1.8ghz or Intel 1366 1.86ghz Xeon Processor
Intel 975bx Chipset Mainboard or Gigabyte X58A Mainboard
Corsair 1050watt PSU
Seagate Hard disk
2 x 5870s & 1 x 7970
or
1 x 7970 & 1 x 5870
or
1 x 7970 & 1 x 7950

Software:

Windows 7 64bit
Windows 8 64bit
cgminer 3.11, 3.0,2.11, 2.10, 2.9, 2.8, 2.7, 2.6, 2.5 2.4
AMD SDK 2.8 and above
AMD Video Drivers 12.8, 13.1, 13.4


I simply cannot run more than one card plugged in, or CGminer runs hundeds or thousands of HW errors, and doesn't submit any shares.

As you can see, I have tried so many different combinations.

When I run cgminer 3.11 and mine bitcoin, all cards hash perfectly. 430mh/s from the 5870s each, and just a touch over 700mh/s from the 7970.

I have even tried underclocking the cards heaps to try and get them to at least run, but nope, massive amounts of hardware errors.

Most of the time CGminer crashes just as it tries to load.

Few other points:

- VRMs aren't getting hot.. the cards don't even start
- Each card works fine if installed on its own
- Still hardware problems if cards are installed but disabled in cgminer

Can anyone help me?

[phrozenspite]

how much ram do you have

[BrainShutdown]

how much ram do you have

Yes it could be RAM quantity and/or quality 

[WeissJT]

Thread concurrency for each card?

[The Mafia]

Its only got 2 gigs of ram in one machine, the other machine had 8 gigs and had the same issues.

I was using 8192 for the 7970 and the 7950

cgminer --scrypt -o http://us.mining.coinpool.in:3333 -u xxxxx -p xxxxx -I 13 --thread-concurrency 8192 -g 2 -w 256 --lookup-gap 2 --gpu-fan 75,75 --temp-overheat 85,85 --gpu-engine 950,900 --gpu-memclock 1375,1200

But I would get this error:

http://users.on.net/pacey/bit/starterror.JPG

If I remove all settings and just run a basic command line, I get this:

cgminer --scrypt -o http://us.mining.coinpool.in:3333 -u xxxx -p xxxx -I 13

http://users.on.net/pacey/bit/hwfailure.JPG

[Foamy]

setx GPU_MAX_ALLOC_PERCENT 100

put that in cmd prompt and this should fix ur problem.

[The Mafia]

Tried that, no luck

Dropped 4 gig of ram into it too, and still no luck.

[bengx]

I was having problems with CGminer for a while too, exactly the same issue with you but I fixed it with some tweaking. Try adjusting the worksize in the config file, and try lowering the thread concurrency. I'm currently running one 5850 and one 6970.

[The Mafia]

Holy shit?

I dropped the worksize to 64 and it actually started to work?? I did this about a week ago and for some reason it didn't work...!

I will test a little further and let you know

[The Mafia]

I have now installed 2 x 7950 and 1 x 7970 and the worksize is at 256 and works ok now.

ONly problem is with 3 cards installed I get

7970 - 450kh/s
7950 - 200kh/s
7950 - 200kh/s

Increasing the intensity seems to help a bit but not much at all.

On their own, these cards go well over 600kh/s each

[shantee]

decrease the intensity under try 12 or under even under 10 - 8

[The Mafia]

Unfortunately that brings the hash rates down to 50kh/s each

[lopheaded]

I have now installed 2 x 7950 and 1 x 7970 and the worksize is at 256 and works ok now.

ONly problem is with 3 cards installed I get

7970 - 450kh/s
7950 - 200kh/s
7950 - 200kh/s

Increasing the intensity seems to help a bit but not much at all.

On their own, these cards go well over 600kh/s each

Hello,
  could you post your .bat and/or .conf ?

[The Mafia]

I don't run a conf file, but here is my batch string:

cgminer --scrypt -o http://us.mining.coinpool.in:3333 -u hunglikehorse -p hunglikedonkey -I 15 --thread-concurrency 8192 -w 256 --lookup-gap 2 -g 2 --gpu-fan 70,70 --gpu-engine 1080,950 --gpu-memclock 1500,1400

This gets 500kh/s out of the 7970
and 400kh/s out of the second 7950. I have taken the 2nd 7970 out because it gets too hot