I am running a VMware XP sp3 on a Vista host laptop Precision M4400 IntelCore Duo 2.66Ghz 4Gb RAM and 64bit OS. One harddrive not partitioned. The performance is very slow. I have defraged de Host and Vmware several times. Do not have any idea why is so slow. Any ideas?


I would suggest starting performance monitor on the host, and then starting the guest vm computer. My guess is that you'll see the Disk Queue pegged at the top most of the time, causing the slowness. If not, post what you do see as the bottleneck.

I have a similar setup. The RAM is ok, and the CPU is ok, but the high disk queue causes the guest OS to be very slow.


There are two major categories of bottlenecks:

  1. Disk I/O (the most common culprit for VMs)
  2. CPU

Watching the CPU meter is an easy to way to know if it's CPU-bound. To know if it's disk I/O bounce is a little bit more work (at least for me). But it's not hard at all. Use a tool called Iometer, which is a storage performance testing tool. You should be able to get a decent comparison of performance by running the same test in your non-VM OS against your VM OS. I have a little blog entry on the subject here.

If it turns out to be CPU bound and you have a 2-core CPU, try turning down the number of CPUs in the VM configuration to 1. I don't know why exactly, but I was majorly CPU-bound on my laptop, and that turned out to be magic change. A lot of others on the vmware forums have found this to be true as well.

If it turns out to be I/O bound, and you really need the performance, you can either use a fast external drive for the VM, buy a solid state drive, or use a different solution like bootable VHDs (if you're on windows). (Sorry - I'd post links to more of this stuff, but as a new user, I can only include one link. For the VHD solution, google for 'Hanselman bootable VHD')

  • On the vCPUs, I believe the reason is that if you specify two vCPUs, the VM has to wait for both cores to be free before it can execute an instruction. So if you run multiple vCPUs you want to have 2x or 3x cores. I'm not a VM expert by any stretch but I was just reading something about that. :-)
    – user19509
    Oct 31 '09 at 22:21

Did you tried running your vm on an external HD, or do you have e-sata?


You can expect reasonably good performance (80-90% of native performance for most things apart from graphics*) from a VMware Workstation Virtual Machine with a very responsive user interface provided you have installed VMWare Tools in the Guest, the tools install upgrades things like the VM disk driver, graphics driver, network driver and mouse with versions that are key to providing optimal performance. You should configure the VM with sensible resource values - it will be easier on the Hypervisor and host if you assign a single vCPU and 1 to 2GB of RAM, if you set the spec on the VM too high then resource contention will be a problem.

I run VMWare Workstation on very similar hardware to you (2.66Ghz Core Duo, Vista, single harddrive) and it performs well provided the host OS isn't already stressed.

*VMWare Workstation 7 and the new VMware Player have significantly improved graphics performance amongst other things.


Your issue is almost certainly disk I/O. Upgrade to a 2nd gen SSD or use an external drive to run the VM.


Have you checked that VT-x is enabled in the BIOS? Performance will be a LOT worse without it.

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