Hello everyone, this is my first post!
There seems to be a lot of controversy about the MSI R9 280X Gaming 3G OC 38SB version.
I get 760K hash, undervolted to 1137, running at 70-72 degrees with GPUs fans locked between 30-75%
Full disclosure: I use a milk crate as a case. I have a box fan setup on the PCI side of the GPUs blowing towards the power connection side.
I read this card can be undervolted to 945mv and put out 650K hash rates; however, I have not tried it myself, yet. I am a total newbie, so an additional 100K hash is more interesting now.
Here are my CGMINER settings:
./cgminer --scrypt -o stratum+tcp://
-u -p -g 2 -I 13 -w 256 --auto-fan --gpu-fan 30-75 --temp-cutoff 85 --temp-overheat 80 --temp-target 72 --gpu-memclock 1500 --gpu-engine 1080 --gpu-powertune -20 --expiry 1 --scan-time 1 --queue 0 --no-submit-stale
Please note the price of these cards, and many others, are well above MSRP at most shops. I would encourage each of you to be patient and order from the smaller shops not looking to gouge your eye out (Google Shop BLT).
If you’re having trouble flashing the 38SB version to an older bios to undervolt:
Read these instructions to get familiar with what you will be doing: http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/
Now go do everything below.
Materials:
USB Thumb Drive
Software:
ATIFLASH (to flash your BIOS)
VBE7 (VBE7.0.0.7b.exe) [to modify your BIOS]
HP USB Disk Utility (to write the DOS bootable disk)
MS-DOS System Files (to make a DOS bootable disk)
Download ATIFLASH:
http://www.techpowerup.com/downloads/2230/atiflash-4-07/start?server=6
Download VBE7:
http://www.techpowerup.com/forums/showthread.php?t=189089
Download HP USB DISK Utility + MS-DOS System Files here:
http://rumorscity.com/2013/12/04/how-to-create-a-dos-bootable-usb-drive/
(password: rumorscity)
Download this BIOS! (***ONLY FOR MSI r9 280X cards!***)
http://www.techpowerup.com/vgabios/149351/msi-r9280x-3072-131029.html
Rename the new BIOS new.rom
Load the HP USB Disk Utility Program, point the software to the win98sys directory (from the MS-DOS System File extraction), pop in your USB thumb drive – make it go! When it’s done, toss on the ATIFLASH, VBE7, and new.rom at the root level of the thumb drive [e.g. f:/atiflash, f:/VBE7, f:/new.rom].
Load VBE7 from the thumb drive, open the new.rom on the thumb drive. Look at this link:
http://rumorscity.com/2013/12/09/how-to-modify-video-bios-to-undervolt-gpu-in-linux/
In section 3 and 4, write 1137. VDDC should read 1137 now, save the rom (overwrite the new.rom file).
Now let’s back up the roms on your GPUs (let’s do both positions, just in case). Look at the link again: http://rumorscity.com/2013/12/09/how-to-modify-video-bios-to-undervolt-gpu-in-linux/
Go to step 7, look at the pic of the switch and locate yours.
Pop in the USB bootable thumb drive you made.
Assuming everything booted up, and depending on how many video cards you have, you’re going to go from 0 (the first one) to the last, saving off the first position’s bios.
To explain what you’re doing:
[program] [parameters; such as –s, -f, -p][device][file]
atiflash -s (save) 0 (first GPU/Device 0) 0first.rom (the file name we gave it)
I have three GPUs connected at the same time, so mine look like this:
atiflash -s 0 0first.rom
atiflash -s 1 1first.rom
atiflash -s 2 2first.rom
Poweroff/flip GPU switch to second position/save second position bios
atiflash -s 0 0second.rom
atiflash -s 1 1second.rom
atiflash -s 2 2second.rom
Type ls, ensure you see all copies of roms on your flash drive.
If you do, now we do the bios flash! Let each one finish, reboot after you flash your last device.
atiflash -f -p 0 new.rom
atiflash -f -p 1 new.rom
atiflash -f -p 2 new.rom
REBOOT! Ensure your flash works (if it comes on, you should be good!).
Get back to mining!
http://s28.postimg.org/4xmatpd0t/useme_760.jpg 
