Hi guys,
I am desperately looking for help. I've been looking for a fix for days on this forum and google without success yet.
The problem is that my rig cannot mine on four GPUs without crashing and rebooting randomly. The longest I was able to mine on four GPUs is 7 hours, but on average my rig crashes within an hour of mining.
Here is my component list:
Asrock 970 Extreme4
AMD Sempron 135
4GB of RAM (Hynix)
4x Asus R9 280X DCU2 Top
2x 850W Akasa Cobra 82% efficiency (two GPUs on each PSU)
3x powered riser 1x to 16x
1x unpowered riser 16x to 16x
Windows 7 x64 Ultimate
CGMiner 3.7.2
Drivers AMD 13.12
Here is my .bat file:
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
C:\cgminer-3.7.2-windows\cgminer.exe --scrypt -I 13 -w 256 --thread-concurrency 8192 -g 2 --auto-fan --temp-target 75 --temp-overheat 85 --gpu-engine 1080 --lookup-gap 2 --gpu-memclock 1500 --scan-time 1 --queue 0 --no-submit-stale -o stratum+tcp://(pool) -u (user) -p (pass)
Total hashrate is about 2.96 Mh/s
The funny thing is that it runs normally without crash with 3 GPUs.
At first, I thought it was a riser issue, as I had lost hair trying to make my rig detect my GPUs, just to figure out that it was due to faulty risers. I swapped them, but still crashing.
Then I reinstalled my drivers, no change.
Then I thought it was due to a temperature problem, although my cards run at 82° for the hottest. Still, I put a temp target to 75°, and it still crashes randomly.
I think that 850w x2 is enough for four of those cards, am I right?
Can anybody help me please? It is so frustrating...
(PS: I run the same .bat file on my main PC with one 280x, and it just rocks!)