I switched to this vm a month or so ago cause of the same problems that came up. I think that I was getting more ppd from error's vm but so far this client is working good. A few things are happening because of Stanford's software that are causing errors to come up but everyone is having the same problem so hopefully it will be fixed up sooner than later.
Vmplayer is what I am using right now on xp64 but I have though of installing the server version to see what I can get out of my quad for ppd, don't know as yet if I'll follow through with this plan but...
I am just waiting for the end of the month to get a proper wireless router/switch so I can hook up my other sli mobo and run another one or two gts250's to add to my total. Until then I can't get over 20k/day.
So are you saying this vm is core limited? Ie you need server for quad?