Well it's hard to say, two 3870's will be cheaper but possibly louder, definately hotter and draw considerably more power both at idle and load.
3870X2 - idle ~200W - load ~400W
1x3870 - idle ~185W - load ~285W
1x8800GTS - idle ~200W - load ~325W
So if you're after a lower temp, lower power draw but crossfire performance in ONE slot, then perhaps the premium is worth it?
3870X2 - idle ~200W - load ~400W
1x3870 - idle ~185W - load ~285W
1x8800GTS - idle ~200W - load ~325W
So if you're after a lower temp, lower power draw but crossfire performance in ONE slot, then perhaps the premium is worth it?