r9 280x: Mine @ 700 KHs, then 4 KH/s, then 700 KH/s ??

[N[e]wBie]

 
I will reboot, it auto runs the bat:
-I 13 -g 2 -w 256 --lookup-gap 2  --gpu-engine 990 --gpu-memclock 1500 --temp-target 70
and I will be hashing along fine at 7xx KH/s. Then, it slows down to a halt, 4 KH/s. Video is fine, games even work fine. I close cgminer, restart, 1-36 KH/s. I reboot, 7xx KH/s. What gives? (windows 7 64 bit 13.11, with and without SDK 2.7)

[EvertonFan]

if it goes above 70, it will turn off or at least slow the hashing down...get some good cooling and you will never go above 79* and its much easier to manage!

[kylejustknows]

if sounds like cards got sick (happens when driver crash and amd driver-auto-recovery kicked in, then the card will remain functional but mining slow as part of the memory is filled with junk)

try rise your voltage a 20mv, reinstall drivers and see.

[kylejustknows]

to evertonfan, the 280x minimum core speed is 400mhz in that case of overheating, his still be mining at 350kh/s, not like a 4kh.

to newbie, set your target temp to 92, overheating to 94, shutdown temp to 95.  This will slow down your GPU fan a lot. The fan bearing will be the first part wearing out in few month if its runing 100% speed. And AMD said 94 degree is perfect for 280x cards and I find it so. Plus it will make your pc much quieter and you can be sure that cgminer will almost never slow you down for protection.

[N[e]wBie]

its auto running at 4-36 KH/s now with the exact same settings after a reboot... is it possiblel its using my onboard graphics card "sometimes"?