Memory how far should I be able to push it?

[Timoty]

I have some new memory and need to know how to push it a little farther.

System specs

Coolermaster Conros 1000 with 6 120mm fans
Thermaltake V1 CPU Cooler
Asus P5N-E SLi
E6600 at 3 GH (FSB at 1332)
BFG 8800 GTS OC 320MB @ 600 Core and 850 mem
2 Gig of corsair cm2x1024-6400c4
Audogy 2 ZS
Seagate 400 GB Sata 3

The memory is unlinked and running at 800
The timings are 4-4-4-12-2 with the TRC at 24 and the voltage at 2.08

System idles at 33C (Core temp) and after 30 min of Orthos at 52C

So my question is this:
If I link the mem and keep the timings the system won't post. If I set it unlinked it won't post at 900 with the timings set as above. Tried 5-5-5-12 and still no post.

So any help with what reasonable expectations should be and how best to get there would be appreciated.