个人总结：
1.删除已经关闭不用的虚拟机。
2.删除虚拟机中不适用的设备。虚拟机配置中和虚拟机系统里面。
3.优化虚拟出的操作系统。
4.确保安装了新版本的vmtools。
5.避免过量分配内存。为主机配置足量的内存。
 
下面列出了一些可以在虚拟机里停用或禁用的通用Windows服务，请根据虚拟机的应用情况具体分析。
Alerter
Clip Book
Computer Browser
DHCP Client (Unless using DHCP IP addresses)
Fast User Switching Compatibility (Windows XP)
IMAPI CD-Burning COM Service (Windows XP)
Indexing Service (Unless needed)
Internet Connection Firewall (ICF) / Internet Connection Sharing
IPSEC Services
Messenger
Network DDE
Network DDE DSDM
Network Location Awareness (NLA)
Print Spooler (May be needed in some cases)
Remote Desktop Help Session Manager
Remote Registry (May be needed)
Routing and Remote Access (May be needed)
Smart Card
SSDP Discovery Service
System Restore Service (Windows XP)
Telnet (May be needed)
Themes
Uninterruptible Power Supply
Windows Audio (Windows XP)
Windows Image Acquisition (WIA)
Windows Time (May be needed)
Wireless Zero Configuration