^+1 for bluescreendeath
If it was me I would add another 3870 until I could save up for a better card, assuming you can get the 3870 cheap of course. Still, I was running dual 3850s for a while and CF support can be a little buggy on the 3800 cards, not to mention the ATI driver team is providing fixes mainly for 5000 series cards and just keeping the 3000 series cards in there as comparability. Then again, my second card was a vision overclocked 3850 that caused both cards to simply show up as "3800 series" cards in the drivers, so my experience was a little a-typical ^_^
Yea both of my cards are clocked to gpu clock : 800 mhz , memory speed: 1170. Also my system recognizes them as 3800 series.