内存运行的频率还有CPU有关，如果是CPU的频率是800MHz，那么即使内存是1066MHz，还是会运行在800MHz的频率下。
例如，CPU是E7520，在Intel的官方网站可以查到频率是800MHz：
http://www.intel.com/design/intarch/manuals/300281.htm

Intel Xeon Processor with 800 MHz System Bus, Intel? E7520 Chipset, and Intel 6300ESB ICH Development Kit User's Manual

The Intel Xeon Processor with 800 MHz System Bus, Intel E7520 Chipset, and Intel? 6300ESB ICH Development Kit comprise an IA-32 based dual-processor platform. This platform serves as a reference for OEMs development platform. This and other development kits from Intel provide a fully working product with range of performance options which can be modified or used immediately for product development.