Problem with CGMINER - second card is slower! (R9 280X)

[kreibich]

I've got a problem with cgminer on Windows 7.

Everytime I run cgminer, the first card has lower hashrate than the other one (even when I turn off the 2nd one in cgminer)



GPU: 2x Sapphire R9 280X Vapor-X OC
MB: MSI A78M-E45
CPU: AMD Athlon X2 340 (3.2 GHz, dual core)
RAM: 4GB Zeppelin @ 1600 MHz
HDD: Kingston SSD 60 GB
Power supply: Corsair CX750M (750 W)

OS: Windows 7 Ultimate 64 bit
CGMINER: 3.7.1 (also tried 3.1.1 - the same result)
GPU Drivers: AMD Catalyst 13.12
Latest bios and other drivers (also tried drivers that comes with HW on CD - the same result)

BAT file:
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer --config ./dogecoin.conf

DOGECOIN.CONF file:

{
"pools" : [
   {
      "url" : "stratum+tcp://doge.pool.webxass.de:3333",
      "user" : "kreibich.1",
      "pass" : "x"
   }
]
,
"intensity" : "13",
"vectors" : "1",
"worksize" : "256",
"kernel" : "scrypt",
"lookup-gap" : "0",
"thread-concurrency" : "8192",
"shaders" : "0",
"gpu-engine" : "1080-1080",
"gpu-fan" : "100-100",
"gpu-memclock" : "1500",
"gpu-memdiff" : "0",
"gpu-powertune" : "0",
"gpu-vddc" : "1.131",
"temp-cutoff" : "95",
"temp-overheat" : "85",
"temp-target" : "75",
"api-mcast-port" : "4028",
"api-port" : "4028",
"expiry" : "120",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"gpu-threads" : "2",
"hotplug" : "5",
"log" : "5",
"no-pool-disable" : true,
"queue" : "1",
"scan-time" : "30",
"scrypt" : true,
"temp-hysteresis" : "3",
"shares" : "0",
"kernel-path" : "/usr/local/bin"
}

What could be the problem?

[kreibich]

Tried SMOS Linux with the same result. I don't know why, but LOAD is only 64%:

[kalus]

what happens when you flip the cards?  does the lower hash rate correspond with the motherboard location, or does it follow the card?

[Gleason]

The top one is alot hotter. Swap the cards and see if the new one on top runs as hot, and goes slower.

I have read that with the Sapphire Dual X cards, they will throttle down after a certain temperature, which I believe someone said was somewhere in the 70C range. 

That would be my guess.

-Brian

[suchshibe]

Hi there, did you ever find the solution to this?
I just created this http://www.reddit.com/r/dogemining/comments/1x04jq/just_got_a_second_gpu_which_is_100_identical_to/, and it seems like we have the exact same issue. I too have 2x 280x vapor-x, both of mine are running at 99% load though.. But one of them is mining less but still gets hotter.