Add me to the mix on those seeing incompatibility mixing caps and capless. I've done no modding.

I just added three new cards to my original. With the original in the first slot, it slowly died and dropped to 0, and all the cards seemed to get pretty hot. I moved it to the last slot, and everything seems to be running good (about 3 hours stable now). Although the original card is slower, it was always around that speed, so I don't think it is being negatively affected by the capless cards.