my point was, since you have CF board, and 4870X2 CF would be huge overkill.
instead of buying single X2, you could grab 4870 for about 240 (after rebate, there are still few around) and if required could always get a second one.
It's not easy to take the same exact screenshot, because when using Swift Travel the "landing" location is not exactly the same, you may appear a meter to the left, right, forward or backward, so I've tried to adjust as much as I could. BTW on this game I have noticed a bit of micro-stutering until I removed fraps overlay. No other game had that problem.
from the sound of the stutter/hitch was caused by Fraps. I believe you will fine with single card.