I doubt that you will have any actual incompatibility problems; I have run two HD 7770s together on HCC1 without any problems, though the cards were identical. I doubt that a factory overclock will matter, but it would probably be a little safer to run two 7870s than to mix one with a 7950. Sometimes when mixing Nvidia cards on Folding they obtain the performance of the lower-level card (i.e., with the fewest shaders), though I don't know if that applies to AMD or not in the case of HCC1.

But it is not clear whether you will be running both of them with the GTX 570 on the same motherboard. My HD 7770 is now running HCC1 with a GTX 560 (on Folding@home) without any problems, so it should be possible with double 7870 cards also. The main problem with mixing cards, as you may know, is getting a clean install of the drivers, especially after removing an older card. Be sure to remove the drivers for all the cards from the Control Panel (not the Device Manager), reboot, and then run Driver Sweeper (the new Driver Fusion is even better) before installing the new drivers.

At the moment, I just use my Nvidia card for Folding, and don't have to do anything except exclude it from BOINC entirely with a cc_config.xml file placed in the BOINC data folder.

<cc_config>      
<options>       
<ignore_nvidia_dev>0</ignore_nvidia_dev>      
</options>  
</cc_config> 

But you want them both for HCC1. I have done that with an older version of BOINC, and I think it may have taken an app_info to get both used, since BOINC used to pick up only the faster card. However, with the current versions of BOINC (7.0.36 is very good), I think they are both picked up automatically, though I am sure someone here can answer that if you post the question.


Yes, this is definitely a project where AMD shines, particularly the 7000 series; in fact, the only one I know of where it clearly outpaces Nvidia.


It works fine with Win7 64-bit for me; Driver Fusion will pick up a few more registry entries, but that may not be necessary. I don't think it matters which goes first, but I usually do the display card first if you are using one (using the internal graphics for display would be better though to eliminate lag).

I just added a second 7870 to one of my rigs and the spacing is too tight to put the cards in neighboring slots for xfire. I did do it but one card can't breathe.

Since I don't care about xfire for anything but boinc and since right now 7.0.28 only seems to be picking up one card, what should I do?

I have the avg_ncpu parm set to 1 and count set to .08333 (12 threads total)

Hello twilyth,
Looking at the cc_config.xml page at https://boinc.berkeley.edu/wiki/Cc_config.xml I see:
I think you will need to set this flag to 1.

Lawrence

Added: Duh.. I did not notice that you were using this flag.