Problem with SL on Prescott-core P4s.

Did some testing with the following:

Pentium-D 3.0ghz, dual Prescott core
Celeron-D 310 2.166ghz, Prescott core
Celeron-D 2.4ghz, Prescott core
Celeron-D 2.6ghz, Prescott core
Pentium-4 3.2ghz, Northwood core
Pentium-4 2.4ghz, Northwood core
Pentium-4 2.8ghz, Northwood core
Celeron 1.7ghz, Wilamette core
Pentium-M 1.87ghz, Dothan core
Athlon 64 X2 4800+, dual core San Diego
Athlon 64 3500+, original "clawhammer" core.
Athlon XP 3000+, Barton core

Yeah, it's a big list, but this is what I'm seeing EVERY TIME.

1) On ALL of the Prescott cores, and ONLY the Prescott cores, SL's Help -> About reads the CPU as "Unsupported 3001mhz" or "Unsupported 2411mhz", etc.

2) The prescott cores get a max of 3-6 fps, no matter what the speed is.

3) The Northwood cores and others (except the 1.7 celeron) get 15-18 fps in the same environment.

For example, same memory/graphics/motherboard/hardware etc; the Northwood Pentium-4 2.8 was correctly identified as a "Pentium 4" under SL's Help->About, and ran at ~17fps. Same environment exactly, only change was a chip swap, Prescott Pentium-4 3.0 was running at 7 FPS, less than half.

So, all I can say is -something- is wrong here, I dont know what. But I've had similar reports from other SL residents who use Pentium-D or Celeron-D processors.

So THAT's what this might be?!?! I didn't know it was particular to certain architectures of processors, and don't know why it is. But now that you've laid this data out--thank you Michi--it sounds *very* familiar. I know some Resis who've said, "Why does it say my CPU is unsupported?" I don't know why, but it could be detected clearer!

Please send a bug report about this so our bug hunters can investigate, sounds like you've got a good lock on it. Thank you for the info!