Re: gtx260 and hybrid sli
Hybrid SLi to boost performance only works with low end cards like the 8400. There is actually a small performance hit when using Hybrid SLi with a highend card like the 260, it is negligible though and you only lose 1 or 2 fps.
The purpose of Hybrid SLi with on high end cards like the 260/280GTX is Hybrid Power, to shutoff the dedicated graphics when just webbrowsing and stuff. But even Hybrid Power doesn't work properly with the 2XX series, it saves a measly 5W of power (which come from turning off the fan) but makes the card very very hot.