I am analyzing software performance problems on a VMWare virtual machine running Windows 2003 Server Standard Edition.

I can see that the assigned memory is 3.75 GB in the computer properties dialog. Is it possible that the VM RAM configuration causes performance problems? )The installed applications would normally run fine with much less, 2 GB or so, as I can see that average memory usage is quite low).

Update: the entire server is performing badly - task manager shows quite low average CPU load for a running database server and some background apps and a virus scanner, but opening Explorer Windows, starting applications ans switching between windows takes a very long time, often more than 20 seconds.

The Server OS is a 32 Bit System. The VM runs in the remote customers IT environment, we are connected over RDP and Internet VPN client. (Performance is bad regardless of connection through external RDP or Intranet VM Console)

It is a VMWare ESX(i) 3.5 installation and the VM was not created by conversion from a physical system.

One strange performance value is the CPU load of the taskmgr.exe application - if it runs, it has a constant CPU load of around 20-25%. The Windows Performance Monitor diagram shows the same value, if I close the task manager, the Performance Monitor also drops to almost zero percent.

  • Is there a reason for precise 3.75? Try with 3GB or 4GB - are you running 32bit and 64bit? Is the entire server that's performing bad, or is it in an application? May 27, 2011 at 8:28
  • @Deani see my update. Thanks for suggesting 3GB
    – mjn
    May 27, 2011 at 8:49
  • At you connected through VM Console, or RDP? Also, are you running in an ESX / ESXi environment, or what platform is used for the VM? Is it a new VM or for how long has the VM been running? Did you eventually convert it from a physical host recently or? May 27, 2011 at 8:59

2 Answers 2


Does the ESX server/cluster runs more than one VM? VM is running on local storage or external storage? Because I/O may be a bottleneck try to measure VM disk queues lenght using Server 2003 Performance counters. Also have a check on your network while connecting via RDP to the VM. Sometimes the VM seems to run slow because of you are connecting via RDP over a slow connection, so try to logon locally (ESX console) instead and compare VM response times.

  • Thanks for the hint regarding connection speed! The customer tested and said local performance is bad as well. We'll analyze I/O (disk queue length) too
    – mjn
    May 27, 2011 at 9:41
  • Did the customer check ping on from the vCenter Console box to the ESX host and to the VM (the server itself)? May 27, 2011 at 13:33

I'd say it's probably not a VM issue but instead a windows issue. Are client/server applications like file access slow as well?

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