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Windows NT Disk Performance on Multiprocessor Hosts
Some users have seen a problem in a VMware Workstation virtual machine using IDE virtual disks on a multiprocessor host computer. The I/O issue is especially noticeable when the virtual machine is booting.
Note: Performance in Windows NT guest operating systems may also be affected by disk fragmentation on the host computer. For details, see Configuring and Maintaining the Host Computer.
Improving Performance
You may increase performance by enabling DMA (direct memory access) on the virtual hard disk's IDE channel in the virtual machine.
If you have a virtual disk and a DVD/CD-ROM attached as master and slave to the primary IDE controller (channel 0) and you want to enable DMA, power off the virtual machine and use the Virtual Machine Settings editor (VM > Settings) to move the DVD/CD-ROM drive to the secondary IDE controller (channel 1) at IDE 1:0.
You can enable the DMA feature after you finish installing Windows NT. You must install Service Pack 6a. Download DMACHECK.EXE from the Microsoft Web site
( support.microsoft.com/support/kb/articles/Q191/7/74.ASP) and run it.
Click the Enabled option for the IDE controller and channel configured for the virtual disk. Typically, this is channel 0 only, unless you have the virtual machine configured with multiple virtual disks and no virtual DVD/CD-ROM drive.
As noted above, you should not enable DMA on an IDE channel with a virtual DVD/CD-ROM drive attached.
Linux Guest Operating System Performance Tips
This section offers advice for configuring a Linux guest operating system for better performance inside a VMware Workstation virtual machine.
Note: This document pertains to the guest operating system that is running inside a VMware Workstation virtual machine. It does not describe actions that should be taken on Linux running on the host.
Guest Operating System Selection
Make certain you have selected the correct guest operating system in the Virtual Machine Settings editor—VM > Settings > Options.
VMware Tools
Make certain VMware Tools is installed. VMware Tools provides an optimized SVGA driver and sets up the VMware Tools service to run automatically when the system starts. Among other things, the VMware Tools service allows you to synchronize the virtual machine's clock with the host computer's clock, which can improve performance for some functions. You can install VMware Tools by choosing VM > Install VMware Tools.
Disconnect CD-ROM
Using the VM > Removable Devices menu, disconnect your CD-ROM drive if you do not need to use it. Disconnecting CDROM devices reduces CPU usage.
Install in Text Mode
When you are installing your Linux guest operating system, use the text-mode installer instead of the graphical installer if you have a choice. This makes the installation process faster.
If you do use a graphical installer and if you are using a Linux host computer, try to run VMware Workstation in full screen mode during the installation.
Full Screen Mode
Run your virtual machine in full screen mode. Click the Full Screen button on the VMware Workstation toolbar.


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