VMWare performance tweaks on Linux (win xp guest)

I upgraded my Gentoo Linux box very recently. I don’t do it very frequently, so this implied major changes in almost every component in my system. This includes the kernel and the vmware workstation I use. Sadly this did not go as smoothly as I wanted. The KDE desktop became very unstable and the vmware became painfully slow. I use vmware to run certain windows applications, for which I don’t have feasible Linux alternatives (very few actually). Fixing KDE was very easy, I tried XFCE and fell in love with it. With vmware I struggled for days to fix this issue, so I think my findings may be useful for others.
Versions
  • Kernel: 2.6.25.x -> 2.6.30
  • Vmware workstation: 5.5.x -> 6.5.3.185404
The problem
The windows XP running in Vmware was so slow that the result of a right click (for changing properties) took 3-5 minutes. The system boot took around 30 minutes. This was not just a bit slow, but unusable.
How to fix
here I don't want to bother you with the way I found the solution. This is the place to help you not to struggle like me.
Kernel config
as you may have already noticed, there are two places where virtualization and vmware related options could be set. One is 'Processor type and features' and the other is 'Virtualization'. The way I understand is this: if you compile a kernel to be used inside a vmware (as guest) then you should set the former. If the kernel is to be used as the host, then virtualization part is where to go. My case is the latter.
Processor type and features
As you see, the 'Paravirtualized guest support' is disabled. To my understanding this option is only useful, when this kernel is to be used inside the VM (linux guest). My experience is this must be disabled to fix the slowdown. 'Tickless system' is turned on as vmware advised so. The other options are to support my Core2 laptop.
Virtualization
There are a number of options to be set here. None of them had any positive effect in my case. The opposite is true however. If I hard compile (not modul, static link-in) the KVM/Intel part, them vmware will not work at all. I left them here as modules, but I don't recomend you to do so, because if KVM/Linux is loaded then vmware will not start.
vmware settings
there is one option I set in the 'Advanced Hard Disk Options' dialog: Enable write caching. This acceptable for me as the applications I use inside the vm are not critical and also I have regular backups.