There are several things you can do to enhance ESX performance, including using multiple physical disks, such as SCSI disks, Fibre Channel LUNs, and RAID LUNs.

Following are some recommendations for enhanced performance:

RAM – The ESX host might require more RAM for the service console if you are running third-party management applications or backup agents.

Network adapters for virtual machines – Dedicated Gigabit Ethernet cards for virtual machines, such as Intel PRO 1000 adapters, improve throughput to virtual machines with high network traffic.

Disk location – For best performance, store all data used by your virtual machines on physical disks allocated to virtual machines. These physical disks should be large enough to hold disk images used by all the virtual machines.

Processors – Faster processors improve ESX performance. For certain workloads, larger caches improve ESX performance.

Hardware compatibility – Use devices in your server that are supported by ESX 4.0 drivers. See the Hardware Compatibility Guide at http://www.vmware.com/resources/compatibility.