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I recently bought Radeon 7970 Vapor-X cards to set up a new mining rig. These cards seems to be performing about 50% out of the box compared to other 7970 cards. Does anyone have experience with these? Can they perhaps be flashed back to a "regular" non-ghz edition bios to improve mining performance?

My first rig is running at 725-735 kh/s per card overclocked (500+ kh/s out of box). It's using the XFX 7970 Core Edition cards that i can't seem to find in-store anymore. I have an identical setup (motherboard, cpu, memory, psu) using the Vapor-X cards, and those cards are getting about 300 kh/s. After several hours replicating the overclock settings to match the XFX radeon's I still cannot get more than 550 kh/s with further tweaking. I have tripple checked all settings and I am now considering returning these cards for cheaper editions that can perform better. All thoughts, tricks, or comments are welcome.

The cards will be returned in 7 days if there is no solution. Would like to receive advice on which cards would do 700+ kh/s except the xfx 7970 core edt.

I have this exact card and same problem! Can't get it to break 600Khs.  Have you made any progress?

how'd you get to 600kh with it?  I'm stuck at 500kh with mine

Are you setting the thread concurrency?

i'm having the same issue :/ however i noticed there's a booster button on the GPU, where the tiny Sapphire brand logo is. http://www.overclockersclub.com/reviews/sapphire_hd7970_vaporx_ghz/

What are your core/mem clocks? 7970 is extremely sensitive to the ratios of these two.

I'm having the same trouble... Was thinking it might be my motherboard/CPU/RAM since it's an older setup with only 2GB of RAM. I'm hitting a max of 400kH/s but even that seems unstable.

I bought two identical cards at the same time and they both behave the same. While trying to tune one of the 7970's received the error below when trying to increase TC to 10240 from 8192. This was with an intensity of 13 and autofan. Was just following the tuning guide from https://github.com/ckolivas/cgminer/blob/master/SCRYPT-README Anyone know what LG is? I've never seen a reference to that setting before. Is buffer memory referring to the card's RAM or the system RAM?

[2013-04-10 03:21:52] Maximum buffer memory device 0 supports says 536870912
[2013-04-10 03:21:52] Your scrypt settings come to 671088640
[2013-04-10 03:21:52] Error -61: clCreateBuffer (padbuffer8), decrease TC or increase LG

Thanks for the help, hope we can figure this out...

I had exactly the same problem with that GPU. I sweeped over different memory frequencies and then adjusted the main clock frequency. What worked for me was:

--worksize 256 -g 2 -I 13 --lookup-gap 2 --gpu-engine 950 --gpu-memclock 1500 --shaders 2048

With these settings I get approx. 650 khash/s on each 7970 according to cgminer.

But then I have a problem with cgminer not submitting shares to the pool, almost all of them seem to be local and pools show 10 khash/s at most. Any ideas what I'm doing wrong? I tried different pools, different coins, same result. Sha-256 mining is OK though.

You can push these GPU's to at least 595-615 kh/s by using an extreme memory overclock.
I have core voltage at 1080 (default 1200) with the core clock set at 856 mhz (performance drop at 857 or higher). Then tuned the memory voltage between 1625 to 1630 (default 1500). When the memory is overvolted you can turn up the memory clock to 1775-1785 mhz. Be sure to run Intensity at 13 in cgminer.

I have reverted from these settings to save power as the extra kh/s are not remotely worth it. Core voltage is now set to 960, core clock is now down to 678. Mem volt at 1500, mem clock 1225. This gives around 520 kh/s per gpu and they run a lot cooler, thus saving power as well. Intensity 13 still seems to be the big winner as any other intensity lowers the kh/s substantially.

If any others got some good settings or experiences with these cards, please share.

I had this problem, and read about setting "setx GPU_MAX_ALLOC_PERCENT 100" in dos/ms-dos. I couldn't set that as my windows xp didn't have the SetX installed. I had to download it from microsoft, Windows XP service pack 2 tools or something like that. Then I finally was able to use the cmd, and it started hashing. It was with a 6770 & 6870, but the exact same error you posted.

EDIT: Download for the support tools that has Setx.exe for the solution if you have windows XP like me.

http://www.microsoft.com/en-ca/download/details.aspx?id=18546

You can set it in my computer, if you right click it, then select properties you can find environment variables there.

Was thinking on getting the same card, not too expensive on eBuyer.