Fryguy8 said:with 4 sticks,you might need to use 2T command rate.
Also, just out of curiosity, run sisoft sandra hard drive test. My board was hard locking for some random reason with my hard drive plugged into one of the SATA slots. I changed it to a different slot and it was fine. Would hard lock every time when sisoft probed the drive (yet I got windows installed on it etc.)
Not only is 2T a given with 4 RAM sticks, some mobos will even refuse to run the mem at DDR400 with 4 slots full and revert back to 333 (166mhz), usually you can correct that with manual settings but you'd have to test for stability of 'course (would still need to do 2T regardless).
SATA 1&2 are not locked, SATA 3&4 are locked. If you OC past 220 HTT SATA !&2 become unstable and unusable, nForce3 issue. That may have been your issue regarding the HDD.
Regarding the Crucial Ballistix (Micron -5B G chips), it's pretty good, about on par with the better hand-picked Samsung TCCDs (from OCZ, etc.)... Though recently they changed their specs on the site to 2-3-2 from 2-2-2 so if you want the absolute lowest timings at stock or near-stock speeds something like OCZ's Rev. 2 might still be slightly better.
Ideally you want whatever OC you achieve to report no errors in Windows nor on a mem test program, many people just stress test with Prime but stuff like memtest86 will focus on the memory alone and will tell you how reliable the OC truly is. You can get pretty high OCs with some moderate timings and still be error-free though.