Im going to disagree here just on the side of mining though. I am a Redhat certified engineer (Earned RHCE earlier this year), and I work with RHEL6 and RHEL5 machines for a career. So I totally understand the subtleties between Windows and Linux.
But, there is absolutely nothing available that will allow you to overvolt a a non-reference GPU in linux. There are a multitude of tools for Windows that allows voltage adjustements for non-reference cards. Trixx, MSI Afterburner are just a few. AMDovrdrvctrl will not allow you to adjust voltages on non-reference cards. You also have to modify the BIOS ont the GPU if you want to do anything worth while with AMDovrdrvctrl. You dont have to modify the BIOS to do the same with the Windows tools mentioned above.
The complaint was there was no way to overclock in Linux and that complaint is false. There was no mention of overvolting. Regardless, though, overclocking and overvolting via software is a ludicrous proposition anyway for anything but a temporary measure. I've never understood the trend, honestly. You get shitty results and a bucket load of instability in the long term when you do it via software, this applies to both Windows and Linux. The only thing software overclocking is good for is to find your stable numbers. Once you find those, you should flash your card with those and leave it at that. Software tweaking is a temporary measure and for the purposes of mining, it's completely pointless. If you're going to mine you need your cards to be set to what you're mining with. If you're some hobbiest miner that is only doing it now and again while using the computer for other tasks, then you're probably not going to be using Linux anyway. If you're following this guide then you most likely are serious about mining and have a dedicated box and thus using software to overclock for mining is just wrong on so many levels.
For example, I can overclock all 4 of my GPU's in Windows and they will stay STABLE at higher clock speeds than in ubuntu. In windows I Can run my 3 HD5850's at 950 core 325 RAM at 1.188 volts and they will hash at 360-370 Mhash all day long, below 65-70c. I can also overclock an additional HD5870 in this same rig to 1000 core 350 ram at 1.2volts and it will stay stable.
I have 28 miners running, all of them overclocked in under Ubuntu and the only ones that have stability problems are the 5970's and that's due to some other issues unrelated to overclocking (craptacular VRM cooling mostly). All the 5870's are rock solid at 950/300 with 5 - 8 GPUs per motherboard. There's a problem somewhere else if you are unable to achieve stability only in Linux. Although, I admittedly don't have nor have I used any 5850's, I can't imagine them being much different.
Now, in Ubuntu Natty, 64 bit running SDK 2.4 and Catalyst 11.5 I CANNOT get the stupid GPU's to run for over an hour at 800 core and 300 ram. With these clock speeds I only see about 300 Mhash/sec. These GPU's have the same BIOS settings as they do when I can overclock them in Windows. I have read every post in this thread, and posted questions in several others with no improvement in results.
There is something very wrong with your setup if you're only getting 300 MH/s at 800 core. You should be getting at least 350, which is what I get on stock core on the 5870's. Seeing as you're running 2.4 that probably doesn't help and you should at least be using Phoenix with phatk kernel if you're hell bent on using 2.4 with 5xxx series cards. In either case, moving to v2.1 if you only have 5xxx series cards will improve your hash rate dramatically.
You yourself even mentioned you had no idea how to free a froze GPU in linux. I have not found a way to kill the process or even detach the module from the kernel without causing a kernel panic. I was highly dissappointed to find out that I can run my 3 5850's at 950 and my 5870 at 1000 for days on end in Windows without the first freeze. Linux has never had a great relationship with GPU's (especially ATI).
Absolutely, but I also had the same problem in Windows (which is why I moved to a Linux solution in the first place) - the GPU would freeze and there'd be no way to unstick it without a full power cycle in Windows. The same problem exists in Linux, so there's no advantage there. However, the major advantage with Linux that you don't have with Windows is the fact that I can access the machine through SSH and take care of everything - can't do that with Windows. You have to have a convoluted, slow ass solution like Teamviewer, VNC, LogMeIn or similar just to manage your miners. Monumental pain in the ass.
Please dont get me wrong, I am not trying to minimize what you are doing by helping out in this thread, but I have had no luck in getting the same results in Ubuntu as I have in WIndows, and I absolutely hate that. This mining rig is actually the only Windows machine in my house (I am running Fedora and RHEL Workstation on my personal machines). I have read every post, and tried everything in this thread as well as others. I still cannot get my GPU's stable above 800 core in ubuntu. I am going to try Debian Squeeze 32 bit later tonight, and I may even try a fresh install of Ubuntu Maverick or Lucid since I despise Natty so much.
Then there is something wrong with your setup. I can't believe the 5850's are that much different than the 5870's and after flashing the BIOS of all the 5870's for 950 core / 300 mem, I've had zero problems with the 5870's. Most of them don't even require a voltage tweak, though some of them I've had to bump the voltage a couple notches.
Not true. There are a couple different tools that allow Linux overclocking, which have already been mentioned in this thread.
Personally, I flash the BIOS with RBE and don't even worry about overclocking from the command line. If you can't overclock in Linux, the fault lies with the operator, not with the (lack of) ability. Is it as slick and easy as Windows? Nope, but then again, Windows can't do half the things a Linux machine can in terms of mining, so it's a trade off. I'd like to see you run more than 8 GPUs in Windows. Can you even run more than 4?
My ASUS 5850 DirectCU 725 are virtually impossible to overvolt. GPU-Z cannot pull the bios from the cards. So I instead download a bios version that looks similar from guru3d. The bios works fine. After that I attempt to edit via RBE. No dice. Once I edit the voltage the GPUs are no longer recognized by aticonfig and/or windows. They are "greyed" out. Perhaps its user error in the RBE editor, but I sure as shit can't figure it out.
If I can find a 5850 for cheap, I'll pick one up and see if it's that much different than the 5870's. If you want to send me a copy of your stock BIOS I can take a look at it.
