It doesn't - but be sure you're installing it into a system that has a BIOS overclock option (such as an XPS M1710, 1730, etc.).  IF you don't -- that is, if you install it in an Inspiron, Studio, Studio XPS, Latitude or Vostro system -  you won't be able to run it at full speed.

You can't change the heatsink the system came with at all - nothing else will fit.

I'm looking at installing it in my T2500 CPU XPS M1710! So I guess that means it's all 'Green lights are Go'?

What's the story regarding the ES chips which I've seen advertised on Ebay then please? The chip has this for it's ID number LF80537 T7600G 7703A990 SL9U5, and there is NO mention of ES in any of the garb included on the auction!

Should be -- that said, be sure you DO NOT get an engineering sample (CPU marked with ES).

What's the story regarding the ES chips which I've seen advertised on Ebay then please? The chip has this for it's ID number LF80537 T7600G 7703A990 SL9U5, and there is NO mention of ES in any of the garb included on the auction

Engineering samples are released to OEM and ODM companies by Intel for testing - it's actually a violation of the agreement with Intel to sell them.  They're generally unlocked, but may have defects in the core, and/or may have been throttled by stress testing, etc.  In other words - beyond being  illegal to sell, they may be damaged goods by the time they're sold.  Certainly the sellers are less than ethical -- which makes them suspect.  If one fails, you'd have no recourse to Intel for replacement.

Does this mean that I will have recourse should my working non-ES labelled T7600G fail on me then(due to NO fault or abuse by me), even if I bought it from an un-franchised seller?

Probably not, unless it was originally a boxed CPU.  Tray CPUs carry no warranty to the end user from Intel.

After all this, I find out the CPU can be accessed via my BIOS......Doh! Once again thank you ejn63 for your helpful answers.