Dammit! F@H on 3 of 4 gpu's(295s) but 4th wont work

[Fitseries3]

hey guys...

i managed to get gpu2 running on 3 outta 4 of my cores on my 2 gtx295's.

the 4th will start but then gets one of the following errors...

"UNSTABLE_MACHINE"
"EUE limit exceeded"

or it will keep looping saying that "results where sent" but nothing has even been done.

the other 3 gpu's are fine and the 4th is configured exactly as the other 3 are.

machine IDs are set to 10, 11, 12, 13 for the cards 0 1 2 3

i have the correct -gpu 0, -gpu 1, -gpu 2, -gpu 3 flags amended and the targets point to 4 separate gpu folders.

i have tried different drivers. none of the cards are OCed. fan is at 60% and temps dont go above 70c max.

im running vista 64bit

any help?

[ND40oz]

What OS?

[Fitseries3]

v64. i added it to the first post as well.

[ND40oz]

Does the 2nd card fold on both cores if it's in the system by itself?

[Fitseries3]

each card alone works with 2 going but both cards will only let 3 gpu's run.

kinda looks like a driver problem but i've seen a few ppl folding with 3 and 4 295's(6-8gpu's) in one machine. it has to be possible.