Linux noob here.  I am posting a couple questions somewhat related to this thread because of my need for some HOWTO action.

I followed the 64bit edition of this guide and it's working great for my 4 6790s. (I thought I did my homework on those but now I'm kinda stuck with them and would like to get the most out of them.) Anyway, since I am new to Linux, what can I do to make sure I have everything from this guide properly updated? I am not terribly afraid of the command line, but I still don't know enough about it to just start poking around. Is there anything to update at this time? If so, would someone be so kind as to post the couple lines it would take to get the job done?

I have also seen some posts about 6xxx cards not being able to be adjusted a whole lot. In my case, I am running at 950/850 @ 1.19V. Is there any kind of software utility I could install to let me further underclock my RAM and possibly undervolt to save a couple watts and degrees C?  I haven't had much luck looking around online.  I want to maximize efficiency, profit, etc. So I am looking for the sweet spot and would rather not toast my cards too soon. Perhaps I could even sell them at some point.

In case anyone has a setup similar to mine with really specific suggestions to offer, please PM (or post here for others' sake).

My system specs as follows:

Mobo: 790fx gd70
CPU: Sempron 140
RAM 1GB
GPU: 4x Sapphire 6790   950/850/1.19   
PSU: Corsair AX850

Mining at ~860Mhash/s @ 580W
Temps 65-80C depending on card and location on board

./phoenix.py ... -k phatk DEVICE=1 VECTORS BFI_INT WORKSIZE=256 AGGRESSION=13

I know some info here might be extraneous, but I wanted to post it for posterity and just in case...