Did you never run Memtest on those servers?
No i hav'nt as it can clone a Windows Server 2003 vm into a template but fails when i choose a Windows XP Professional vm.
I have tried the same scenario with and without resource pool. In both the cases, the Cloning to Template went through without any PSOD / BSOD. The configuration details of my setup are as,
Hardware: IBM Server xSeries 346
Processor: Intel Xeon 3 GHz
VI Client Version: 2.5.0 Build: 119801
VMware ESX Version 3.5.0 Build: 140688
VMware VC Server 2.5.0 Build: 119598
VM: Windows XP Professional - 32bit
as it was the fact that vmware is built on linux which only gets tested on older releases of motherboard bios's, so i downgraded them and all is working fine, with vc, ha and drs.