What configuration changes can I make to speed up extremely slow Windows VM's in ESXi 4.0

I've recently moved from VMWare Server to ESXi 4.0. Running on Dell T310. My VM's have been restored but they are running dog slow compared to VMWare Server. I loaded ESXi 4.0 using only default values.

Where are some areas where I can tweak the performance? Even logging onto the VM's can be extremely sluggish. Trying to install software on any of them is a new experience in pain.

Dell PowerEdge T310
Xeon X3460 2.80 GHz
32 GB RAM
1 HD (2 TB)

I have 16 VM's on this server, but only six or so will be running during my testing. I keep an eye on the Resource Allocation and Performance tabs for the host and I never see CPU or RAM getting anywhere close to pegged. Events tab does show some notices for video RAM issues and some hints on Windows activation issues, but nothing that would point to the sort of sluggishness that I'm experiencing.

1 Windows Server 2008 R2 (64-bit) - 4 GB RAM
1 Windows 7 (32-bit) - 2 GB RAM
1 Vista (32-bit) - 1 GB RAM
3 XP (32-bit) - 1 GB RAM

Over to you!

Thanks - Shawn

My guess is that you are running this all on 1 HD. VMware is all about the IOPS and the first thing to go is usually the IOPS. Use ESXtop to check your IO numbers. 1 HD is good for about 150 IOPS

To continue on @Jim B's comment: I'd guess you have a 7200RPM SATA drive since you mentioned 2TB capacity. That drive is going to give you under 100 IOPs, which will really struggle if those VM's are doing pretty much anything with IO.

If it's possible - an option would be to add a SSD drive to your box. If your VM's are thin provisioned(you can convert them with vmkfstools) and don't have a ton of data it would serve you well.