Motu 24I/O driver performance on Vista

[DJ Synchro]

Hi guys,

I have a MOTU 24I/O which I use with Windows XP. I also have a Windows Vista x86 license. I would love to use Vista as my main OS, however, I tried to work with Vista as my DAW, but I have major performance issues in comparison to Windows XP. I use Cubase SX and if I open a project in Cubase using Windows XP I can set my buffer settings to 256 and the latency then is about 6ms. Playback is tight and smooth. On the other hand, when I use Windows Vista and open the same project in Cubase, a buffer setting of 256 gives me major dropouts, pops, clicks an twice as much CPU load (!) I have to set the buffer to 1024 for the project to play without pops. the CPU load still remains twice as much. The latency then is too high for smooth keyboard playing, plugin tweaking etc.
I tweaked my Vista installation and even stripped it down using vLite. Any idea's why this is the deal? Is it just because the drivers are buggy when used with Vista, or is there more to it??? I'd really like to use Vista as my main OS and DAW because I like working with Vista.

[billruys]

I don't think it's a driver issue, because the 24i/o works fine at pretty much the same latency in Vista as it did under XP for me. I'm running Sonar 7 and typically run at 5.8 ms, but can go lower if I need to, but 5.8 ms gives me a solid performance with latency low enough to play instruments real-time. Does Cubase have settings to allow you to take advantage of MMCSS like Sonar does? This gives the DAW application higher thread priority than other apps, making things less likely to pop & click due to background processes stealing processor time.

[DJ Synchro]

I tried different settings in Cubase. Putting the audio priority on highest, but no improvements...
It must be a driver issue, because it's a clean install of Vista and on XP it performs so much better...