Problem with 7950 used for HDMI display

[dudeofthestick]

Dear miners,

I have setup my first litecoin mining rig for testing and I'm not sure if I'm doing something wrong or not.

I have setup a mining rig as follows:

- Coolmaster HAF XB Box
- MB Fatality 990FX Professional Series
- AMD FX 8150 8 Core
- 16GB DD3 RAM CORSAIR
- OCZ 850W ZX SERIES
- 128GB OCZ SSD
- 2 x SAPPHIRE 7950, crossfire cable connected.
- WINDOWS 8 64 BIT
- cgminer 3.1.0
- MSI Afterburner

I have successfully obtained sustained >650KH on one of the 7950, but I can't get more than >500KH in the other. They are equal (or should be equal) and the major difference is the slow 7950 is the one used for the HDMI display in the Operating system. Crossfire is configured, BTW.

I'm wondering if I have to setup a cheap display card and use both 7950 for mining only.

Here goes my configuration details:



And my configuration file:

Code:

{
"pools" : [
	{
		"url" : "stratum+tcp://XXXXXXXXX",
		"user" : "XXXXXXXXXXX",
		"pass" : "XXXXXXXXXXX"
	}
],

"intensity" : "18,20",
"gpu-engine" : "800,1075",
"gpu-fan" : "20-100,20-100",
"gpu-memclock" : "900,1600",
"gpu-powertune" : "20,20",
"temp-cutoff" : "90,90",
"temp-overheat" : "80,80",
"temp-target" : "70,70",

"auto-fan" : true,
"auto-gpu" : true,
"expiry" : "120",
"failover-only" : true,
"gpu-threads" : "1",
"log" : "5",
"queue" : "1",
"scan-time" : "60",
"temp-hysteresis" : "3",

"scrypt": true,
"lookup-gap": "2,2",
"shaders": "1792,1792",
"thread-concurrency": "16384,16384"
}

Also they are undervolted to 1.025.

Any advice?

Cheers

[miningdude]

For starters, your slower card's intensity is at only 18 instead of 20 like the other one. I've had a similar issue while litecoin mining on my rigs, but the differential is usually more like 30 Kh/s difference on my HDMI attached vs non-HDMI attached display GPU.

[phrozenspite]

Try disabling crossfire as well.  It serves no benefit to GPU mining and actually can hurt performance.  use a dummy plug on the card not being used as a display

[Spetznaaz]

As has been said, first thing you wanna do is disable x-fire.

Try -I 13 and -g 2.

I noticed you are using different memory and GPU speeds for each card, any reason for this?

Try 1500 Mhz memory and between 1020 and 1040 Mhz GPU clock.

Have you tried setting the slower card with the exact same settings as the faster card?

[dudeofthestick]

For starters, your slower card's intensity is at only 18 instead of 20 like the other one. I've had a similar issue while litecoin mining on my rigs, but the differential is usually more like 30 Kh/s difference on my HDMI attached vs non-HDMI attached display GPU.

I can't run anything above 18 in the HDMI attached display GPU. I get an error of the driver and the GPU dies. 18 is the maximum value I can use.  

I tried using 20,20 or 19,19. But the card with the display fails.

Thanks!

[dudeofthestick]

As has been said, first thing you wanna do is disable x-fire.

Try -I 13 and -g 2.

I noticed you are using different memory and GPU speeds for each card, any reason for this?

Try 1500 Mhz memory and between 1020 and 1040 Mhz GPU clock.

Have you tried setting the slower card with the exact same settings as the faster card?

I will disable x-fire.

I tried with different GPU speeds because the display GPU does not support the settings of the second GPU. I started using the same settings, and I slowly changed settings until I get a stable configuration.

Thanks!

[Spetznaaz]

As has been said, first thing you wanna do is disable x-fire.

Try -I 13 and -g 2.

I noticed you are using different memory and GPU speeds for each card, any reason for this?

Try 1500 Mhz memory and between 1020 and 1040 Mhz GPU clock.

Have you tried setting the slower card with the exact same settings as the faster card?

I will disable x-fire.

I tried with different GPU speeds because the display GPU does not support the settings of the second GPU. I started using the same settings, and I slowly changed settings until I get a stable configuration.

Thanks!

I had loads of problems with -I over 13, but when i switched to -I13 and -g2 it sorted everything out.

No worries, let me know what you get with those I and g settings