Is anybody here running linux? What are you using to adjust the voltage?
For those with an attention span of a goldfish, the answers are (a) Yes I run Linux wherever I can't use Mac OS X productively; and (b) There are two widely-used Linux tools for tweaking ATI cards - the aticonfig CLI tool supplied by the manufacturer, and AMDOverdriveCtrl, a GUI front end. The AMDOverdriveCtrl GUI app appears to have a voltage adjust bar, so there's your answer. I understand that AMDOverdriveCtrl is just a pretty front end for aticonfig but I haven't found out which options to tweak on the command line yet. Decided to put an abstract in after re-reading the random rant below, heh.
All my mining kit runs Linux (apart from the proof-of-concept OpenCL phoenix setup running on my Mac Pro with a laughable 4870 - laughable being the price that I paid for the card back when it was Apple's 'top non-pro-photog GPU' - adding a steady 80 Mh/s, used to develop all the scripts that monitor various outputs (aticonfig on Linux obviously not available on OS X, but the scripts expand to any output) and make my three (soon to be four) miner boxes easy to monitor from one web page).
This is only because I'm a Mac bloke (Apple make nice hardware and I am a Unix guy, and prefer OS X to Linux on their hardware) - hence it's a natural swap from OS X to Linux. I'm too old for OS religious wars, but I'll only use Windows in a VM on one of my Macs for specific business applications. Clearly, running hardware-tweaking tools within a virtual machine is generally unlikely to work
From a box of bits to a fully running miner with Linux (I'm following the herd and using Ubuntu, of course any distro will work, and anything Debian-based will probably work with exactly the same setup scripts) takes me about half an hour. It's a bit like installing OS X - the Ubuntu lads and ladies wisely used similar user interfaces to the bits of OS X that Apple did well (and wisely avoided the bits Apple screwed right up). Perhaps Windows works as well these days, but it's not an *immediate* straightforward job to write scripts on Windows like it is on Unix systems. Windows is MUCH more GUI-development oriented, and whilst I can't complain about the cost of Microsoft's dev suite any more (to be fair, Visual Studio has always been the best IDE), I really wouldn't want to waste time building a front-end application for this. Equally, the Windows Way tends to require API calls to acquire hardware sensor readings, which is extra code to write. The Unix paradigm has lots of little tools that do one or a few functions, take input (from a file, another program or the command line) and write output (to console, another file, or another program, etc.).
Now you can do the same with Windows. But Unix developers tend to write command-line tools as a matter of course, whereas Windows developers write fancy GUI tools as a matter of course. If you browse back to the thread started by Messhead in Newbies, you'll see his 'Trixx' application - which allows him to do the Radeon tweaks you want. IMO, from a Mac user-interface-design perspective, Trixx is an abomination
However, it will be accessing a bunch of Radeon APIs to do these changes... so you could write code to do this yourself in VB script, C# or C - you just need to find the API headers in the SDK.
With Linux in particular (as this doesn't apply to OS X), AMD have made available an SDK (for which Linux users should be very thankful!) - and the 'standard Unix' approach of a scriptable command line tool is the main controller for their 'Overdrive' tweaking functions. It's called 'aticonfig' and a search here will find that it's used in all Linux miners to show temperatures, change clock speeds, alter fan performance, etc. There is a GUI wrapper for this tool called 'AMDOverdriveCtrl' for those who have screens connected to their miners (or are exporting X sessions across the network to a controller machine - however I prefer to leave the GUI alone on dedicated headless miner machines).
This app has a Voltage tweaking adjuster. One caveat - I haven't ever tried the application, as I currently only use the CLI tool for scripting purposes.
And changing *voltage* is something I've not yet found in the aticonfig tool. To alter fan speed, one uses an undocumented command called pplib-cmd, so the code is something like:
DISPLAY=:0.${gpuIndex}; aticonfig --adapter=${gpuIndex} --pplib-cmd 'set fanspeed 0 ${fanSpeed}'
Running the help output of
aticonfig doesn't mention the
pplib-cmd option. So the voltage tweaking option must be similarly undocumented - it's just a question of finding it. Maybe it's a command for the above 'pplib' option. Then again, there's something called the PCS (persistent configuration store) which, presumably, holds things like the 'committed clocks' that you eventually settle on if overclocking. This has a key/value and array storage system and I'm looking into this.
The number of options AMD have made available in the aticonfig tool is vast - so if they removed voltage control then it'd be a deliberate act to hobble Linux tweakers. Since Linux users tend to be tweakers by nature, and the AMD lads / ladies who wrote the Linux code must be Linux types, I bet it's in there somewhere.
I haven't got the balls to over-volt my cards just yet because I'm still struggling with getting stable temperatures in aesthetically pleasing cases in safe environments. Running the logic boards bare in cardboard boxes in my office works very well, but my office is underground with no air conditioning and I'm cooking. The back room is considerably colder than the rest of the building so I want to put them there... but they will need some protection. Equally, I was concerned about massive power usage, but my dual 5850 overclocked box is currently (sorry, no pun intended) drawing 450W *total* from the wall. So I'm taking Messhead's advice on board and researching how to use the CLI tool to over-volt, assuming I can get GPU temperatures consistently below 80˚C - at the moment they're 90˚C stable.
When I find out, I'll post here.