question nvidia fx 3400 nec acusync lcd 92vx

Hi, I recently install Vista Beta 2 (build 5384 - Japanese localized 32 bit) on HP xw 6200.
Question-A: I noticed that the graphics performance is unaceptably slow, although the overall rating is 4 (processor 5.4, memory 5.8, HDD 4.0, graphics 5.9). Is this because the current driver for Nvidia FX 3400 has not been tuned yet? or FX 3400 is not good enough to run Vista?
Question-B: Very frequently (once per 1 - 2 min), my screen (NEC LCD 92VX) becomes all black and "Processing..." is shown. It seems monitor is seeking the signals. This does't happen with XP. Is there a workaournd for this?
Thanks in advance,
-Sami KOZONO Autodesk, Inc.