Same card, one mines slower than the other?

[bobbobobbo]

2x 7950. Sapphire 4Ls. Installed the latest CGminer and enabled amd overdrive.

1100/1500 clock set, +20 powertune

cgminer.exe --scrypt -o http:xxxx -u username -p password --worksize 256 --thread-concurrency 24000 --vectors 1 --shaders 1792 --intensity 20 -g 1 --lookup-gap 2


I'm getting 515k/hash - 57c and 603k/hash - 75c.

  They're the same card.... 1 other had mentioned it's just slightly defective and will largely show at max usage... ugh.

[1715366122]

1715366122

[brucemangy]

one of your card is busy rendering the desktop.

try linux ^^ ?

[bobbobobbo]

one of your card is busy rendering the desktop.

try linux ^^ ?

I have no monitors plugged in except for a tiny 7" usb monitor.... so don't think that's it?

I will try xubuntu tomorrow.

Anything else anyone can think of? Perhaps my settings are all weird? This is so strange.

[BBQKorv]

If you have recently plugged some cards on and off, reinstalling drivers could help. I have one 7970 underperforming slightly (715khs vs. 730khs) in one of my rigs, it has unpowered riser and I suspect that being the reason. Already swapped to card with another one but no difference. I'll try powered riser on it some day.

[mccminer]

Did you mean to post your readings in Kh/s, or did you mean Mh/s?  The reason I ask is because a difference of 88 Kh/s is not all that much when you convert it to Mh/s. 

For example, the difference in your cards expressed in Mh/s would look like this:  700.000 Mh/s vs  700.088 Mh/s

[ebildude123]

Did you mean to post your readings in Kh/s, or did you mean Mh/s?  The reason I ask is because a difference of 88 Kh/s is not all that much when you convert it to Mh/s. 

For example, the difference in your cards expressed in Mh/s would look like this:  700.000 Mh/s vs  700.088 Mh/s

It's KH/s, he's doing litecoin mining. This difference in speed actually does make a difference.

[mccminer]

My apologies.  I didn't see the '--scrypt' entry in the config line when I originally looked at the post. 
 

[bobbobobbo]

Opened up GPUz. I get Asic qualities of 60% and 67%. One major oddity is that one of the cards reports 1050/1450 while as the other reports 1100/1500. I have them set in AMD Overdrive, I thought it applied to both cards..

Perhaps I will set it through CGminer, will that override overdrive's settings?


edit:: set CGminer to control GPU clock speeds. All is now well. Thank you all.