E8400 Q740A555T@4005MHz 445x9@1.344v
I've got the exact same batch as yours Retro, and running at the same 445x9 @ 1.344v (1.365v iln bios, load line calibration enabled). Most of the "T" 8400's were sold in Canada and Australia. Perhaps the T stands for "tested", as both my sealed retail units (Same batch, I RMA'd my first one due to stuck temp diode) had scratches on the back where they had obviously been pre-tested at Intel (...nope, this one sure ain't no E8500

nope L740Axxx "T" 4.5ghz @ 1.5v seems good. I dunno spectacular, but I've hit 4690 bench stable @ 1.55v.
I hit 4610 @ 1.55v with my "T", but not exactly "bench stable" for more than a short period.

One thing which concerns me is my L2 cache latency of 4.0ns @ 445FSB x 9? I think mine used to be 3.4ns before, using the same Everest Ultimate latency benchmark? Has my cpu degraded, or is this 4.0ns L2 cache latency consistent with other users at 4.0GHz?