The following information was obtained from Dell’s web site:
http://support.dell.com/support/edocs/software/eslvmwre/Systems_Mngmnt/ESXi_MNGMNT/HTML/body.htm
Monitoring Comparison between ESX and ESXi
Systems Management
Feature Description: Inventory
Processor Information including brand, processor version, current speed, core count, model, stepping information, 64-bit support, HyperThreading (HT), Virtualization Technology (VT), Demand Based Switching (DBS), and Execute Disable (XD).
Cache information including status, level, max size, installed size, type, location, write policy, set associativity, and error correction.
ESX Classic
All of the above Inventory information is available through OpenManage Server Administrator.
Processor brand, processor version, current speed, core count, model, and stepping information is also available in IT Assistant
ESXi
Only Processor brand, processor version, current speed, core count, and model available using the VI Client.