Hi,
Glad you got it working after a fashion at least.
Yeah the step code is basically the desig revision of a particular cpu, for example E5400 series cpu's come in C0 & E0 steppings. For most software this isnt an issue but it can cause problems with some stuff.
The easiest way to check if your two cpus are a different stepping is to check the 5 character spec code on each chip;
Example for an E5450: SLANQ = C0 stepping & SLBBM = E0 Stepping.
The processors families for the DL360G5 are at low prices now so it shouldnt be too hard to pick up a cheap replacement if it does turn out your issue is stepping.
Hope this is some help.
Cheers
Mark