Is this the normal limit for stable OC with Core i7 920 (4.2ghz)?

What do you think?

Any higher and OCCT will say its unstable

This is with:
DDR3-1600 OCZ Obsidian 6GB
and
Asus P6T X58 LGA1336

Xbit Labs did an O/C review with the Asus p6T, that asserted the 920 was generally able to get to 3.8GHz with very little or no voltage adjustment needed.

With voltage adjustments (and of course, a very good air cooler), they claimed 4.0 was the maximum stable speed they could reach.

They preferred prime95 fft's and blend mode for stability testing. I have heard that OCCT is more of a memory test, and doesn't stress the cpu as well as prime95. Since the i7 has a built in memory controller, it can do better on memory type tests. That is it's strong point.

From my experience, do some folding for Folding @ Home (on our team, of course ), and you'll have an EXCELLENT stability test.

I've never had a FAH stable OC that wasn't equally stable for all the rest of my every day stuff (games/etc.). FAH is nicer about dubious OCs then P95 is.

Thats way to high Vcore for a D0.