I am building my first miner and am looking at a few designs, a system with 3 x 6990, a system with 3 x 5970 and 3 systems with 3 x 5770.
I am having a hard time calculating the Mhash for this second system though.
Here are the parts.

Chassis	CoolerMaster HAF X	$90	http://tinyurl.com/6hs3myk
Power Supply	Corsair TX850 (TX850W)	$124	http://tinyurl.com/624hm3b
Motherboard	MSI 890FXA-GD70	$175	http://tinyurl.com/6y78afz
CPU	AMD Sempron 140	$37	http://tinyurl.com/6k35b7d
Memory	2GB DDR3	$18	http://tinyurl.com/6e9kkdf
Graphics card	3 * Radeon HD 5970	$1,800 ($600 × 3)	http://tinyurl.com/62hxqpl
Storage	Kingston 30GB SSD	$80	http://tinyurl.com/6xmmd7r
Total	Approximate Mhashes 2011.1754	$2,324 + s/h/t	$1.155533 per Mhash

            


Given this setup, what should I expect for Mhash?

Also feel free to make suggestions for dropping my $$$/Mhash, while still keeping the overall Mhash around 2000