Flashing Radeon HD 7970 GHZ to R9 280X

I'm in perhaps a bit of an unusual situation in that I have a Radeon HD 7970 GHz Edition GPU, direct from AMD. The Vendor ID is 1002 and the Subsystem ID is 3000. The VRM on this card identifies as CHL822x and the memory is Hynix H5GQ2H24AFR. Looking through TechPowerUp's VBIOS catelog, I kept looking for VBIOS that would provided decent hashing performance from this card. Previously, I only managed to hash at around 510-520KHash/sec, which is quite low for a 7970, but the problem appears to be with most 7970 GHz Edition cards. The solution is to flash to a non-GHz Edition -- if you can!

I tried numerous VBIOS options from a variety of vendors -- ASUS, Sapphire, Gigabyte, XFX, etc. -- all to no avail. I had to force-flash most of these, due to a Subsytem ID mismatch, and not surprisingly several of the VBIOS options I tried ended up requiring me to boot up off a different GPU to recover to a working VBIOS. Up until last night, I was met with zero success -- the Sapphire VBIOS I tried flashed successfully and I could usually boot into Windows, but I would get a BSOD any time I tried to tax the GPU.

As you might guess from the title, the solution for me ended up being to flash to a Radeon R9 280X VBIOS. I still had to force flash (ATIWinFlash.exe -f -p 0 R9280X.rom), but the Vendor ID was 1002 and the Subsystem ID was 3001, so I figured I had a good chance of succeeding...and it worked! Thank goodness -- no more of this 500KHash silliness for my 7970 GHz card!

If you're having a similar problem, most likely you're in the same situation and have one of the "not very fast for scrypt" GHz Edition/Overclocked cards. You'll probably have to try more than one VBIOS before you can find one that works, but don't lose hope! Symptoms of the problem are that your 7970 will actually hash slower at intensities above 13, plus as noted the inability to break 600KHash, let alone 700KHash. Here's what I was running prior to the flash:

cgminer.exe --auto-fan --failover-only --scrypt -o stratum01.hashco.ws:8888 -u trogdorjw73.tester -p tester -I 13 --gpu-fan 40-95 --gpu-engine 1050 --gpu-memclock 1550 --gpu-vddc 1.170 --thread-concurrency 24160 -g 1 --temp-target 85 --temp-overheat 95 --temp-cutoff 100

With that configuration and the original VBIOS I was pulling 510KHash, and I really couldn't get it to run any better. With the update to an R9 280X VBIOS, I'm now pulling around 700KHash with the same settings but I 20. That makes for decent hashing but a totally useless system if you need to do anything else, but the 7970 (R9 280X) has an interesting quirk: you can often get equal or better hash rates at lower intensities with -g 2 and a lower thread concurrency. Here are my current "usable PC" settings (and note that the GPU core is now clocked at 1000MHz instead of 1050):

cgminer.exe --auto-fan --failover-only --scrypt -o stratum01.hashco.ws:8888 -u trogdorjw73.tester -p tester -I 13 --gpu-fan 40-95 --gpu-engine 1000 --gpu-memclock 1550 --gpu-vddc 1.170 --thread-concurrency 8192 -g 2 --temp-target 85 --temp-overheat 95 --temp-cutoff 100

Hopefully that will help some of you out, and if you have any of the 7970/R9 280X cards you can use similar settings to get over 700KHash. Considering a lot of R9 290 GPUs are topping out at 750-800KHash/sec (at least using their stock VBIOS), and the R9 290 cards are currently selling for over $500 (never mind the $650+ R9 290X cards!), if you can find a reasonable price on the Radeon R9 280X (some are going for $350) or one of the older Radeon HD 7970 cards (these tend to be more expensive, so look for the 280X first!) it's definitely worth considering.