No prob. To be conservative, just take the speed of one of the 5 Conroes, multiply it by anywhere from 1.25(25% better) to 1.3 (30% better) and you should be fine.
The performance will vary from application to application, even from game to game, so 25-30% is a safe margin. For example, I know I've seen situations where the advantage for the Conroe was as little as 10%, but I also know that Conroes calculate Pi 70% faster than A64s, so there's a wide chance for variation.
PS: When I first read your posts, since our names are so similar, I remember thinking, "I didn't write that..." Lol.