Latest version of the drivers from Hauppauge on a recently installed Windows XP SP1 box. Here's the report from MC:
Media Center Registered 9.0.124 -- C:\Program Files\J River\Media Center\
Microsoft Windows XP Workstation 5.1 Service Pack 1 (Build 2600)
AMD Athlon 1733 MHz MMX / Memory: Total - 1047 MB, Free - 660 MB
Internet Explorer: 6.0.2800.1106 / ComCtl32.dll: 5.82 (xpsp1.020828-1920) / Shlwapi.dll: 6.00.2800.1106 (xpsp1.020828-1920)
Shell32.dll: 6.00.2800.1145 (xpsp2.021108-1929) / wnaspi32.dll: Internal ASPI Layer
Ripping / Drive E: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Drive F: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Drive G: Copy mode:ModeBurstBigBuffer CD Type:Auto Read speed:Max
Digital playback: Yes / Use YADB: Yes / Get cover art: No / Calc replay gain: Yes / Copy volume: 32767
Eject after ripping: Yes / Play sound after ripping: No
Burning / Drive E: PLEXTOR CD-R PX-W4012A Addr: 1:0:0 Speed:40 MaxSpeed:40 Use MJ Engine:Yes
Test mode: No / Eject after writing: Yes / Direct decoding: Yes / Write CD-Text: Yes
Use playback settings: No / Normalization: None