I use it. I have r9 290's and this is the only miner i know of that doesn't crash on restarts.

http://www.reddit.com/r/litecoinmining/comments/1va8g2/ann_sgminer_400_release/

that's the reddit announcement for 4.0, they are on 4.1 i believe now. But that post should link to the newest version.

I would preserve the uefi bios and flash over the non uefi one.  Make sure to save the current one before flashing though of course.  Yeah those bottom two cards are going to overheat no matter what voltage you use.  You can turn down the intensity for now.  Try -I 12 or even -I 11 if you need to.  Or you can pull one card out and run two at full intensity and wait for a riser cable for the other card.  For the hashrate, try the settings I mentioned in the other post to get 740s.  remove -v 1 from cgminer and change tc to 11200 and use 1050/1500, etc.

Yeah man, you're better off editing your own BIOS than taking a risk using one that won't work with your card.  Don't try flashing a different bios unless you are familiar doing all of this because it might screw up your card and then have to take many extra steps to get it working again.

Just follow the cryptobadger post to a T when editing your own BIOS, it's easy as cake.

The thing about Trixx is you have to reapply everything everytime you reboot.  Afterburner doesn't change the voltage on the new cards, at least the last version I tried.  cgminer may or may not in windows, but the values are usually off, it won't control voltage in linux.  sgminer miner though, you might have the best luck with for controlling voltage in the prog.

You should ask 'The Stilt' for a little help, he''l modify your bios for you and hand it right back to you..
https://litecointalk.org/index.php?topic=12369.1980

He fixed my 280x bios, too!

Or you could just check out the repository on that thread..

See djben's post with many fixed 280x bioses
https://litecointalk.org/index.php?topic=12369.msg120143;topicseen#msg120143

See pengo's post with a similar list:
https://litecointalk.org/index.php?topic=12369.msg93754;topicseen#msg93754

-HollowStorm(miner)

Try;

--lookup-gap 2 -I 13 --thread-concurrency 11200 -g 2 -w 256 --gpu-engine 1050 --gpu-memclock 1500 --temp-cutoff 90 --temp-overheat 85 --gpu-fan 90

go in the cgminer folder and delete the scrypt-tahiti.bin files first and whenever you change thread concurrency.  

I remove the vector tag as it slows me down "-v 1".  

Undervolt in the VBE7 with 1100 to 1110 and remove "powertune -20" from the cgminer bat file and just leave it at default which is 0.  Also make sure overdrive is turned off in catalyst control center.

Open a terminal window and type;

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1

I get 740's+ with this setting and my cards run in the 60's in open air rigs.  1080/1500 will get you 765+ but you'll usually have to volt higher. Other sweet spots are 1020/1500, 1030/1500, and some people report success with thread concurrency 10240, or sometimes using --shaders 2048 instead of thread concurrency.  If you push the memory above 1600-1675 your system will start to crash and you'll have to overvolt the memory which you don't want to do.

Scrypt settings are voodoo.  One number in either direction can cause hashrate to drop significantly.  The trick is finding the magic numbers.

Using a pc case though will cause the cards to run pretty hot.

-I 13 --thread-concurrency 8192 --lookup-gap 2 -g 2 -w 256 --gpu-engine 1140 --gpu-memclock 1827 -v 1 --gpu-powertune -20 --temp-cutoff 90 --temp-overheat 85 --gpu-fan 90

try this... if its too hot, use this

-I 13 --thread-concurrency 8192 --lookup-gap 2 -g 2 -w 256 --gpu-engine 1080 --gpu-memclock 1500 -v 1 --gpu-powertune -20 --temp-cutoff 90 --temp-overheat 85 --gpu-fan 90

you should get 730-790 kh/s per card

What is your card exactly? 65-80 C is acceptable...

You have to open your tower if its not.. and to set fans at manual speed 80-90%

Have you created a worker on the pool?

If not, create one on the pool site.. and at -u and -p you place the worker username and password..

If you already done that try to run the .bat without any extra settings to see if it works at all..

lol.. ok found it

it has to be --thread-concurrency
the "-" is important

Yes very good.  VBE7 and cryptobadger's guide is the way to go for sure.  The regular software programs always aren't reliable for correct and consistent voltage adjustments.  For my Sapphire 280x OC's I used VBE7 and set both #5 and #6 options to 1100 for voltage, which ends up showing as 1.019 in the operating system.  The power saving is pretty good, but the heat and temp difference for the cards is significant.  If you let it run for a day without and then change it the next, you'll see.    Mine are rock solid stable using 1100.  But you can always bump a bit higher if you feel like, or if you need to, say 1110.  The exact numbers don't matter as in "1137", etc, as long as it's close.  To maximize hashrate you can just change the clock settings while you're in there too.  Usually 1050 clock and 1500 memory I've found best for mine.  But some people use 1030/1500. 1080/1500 gets slighter higher hashes but usually requires more voltage.  Also memory voltage use 1500.

Also don't forget to flick the bios switch on the cards before flashing. 

Glad to help, and welcome to DigiByte  

I have a bunch undervolted.  Are you using VBE7 or software?