Core i7 2600k

[mjtweedy]

what do I lose by running 32 bit XP on computer with Core i7-2600k?

 

[szbxa]

you can possibly lose some RAM, that's it.

 

[popatim]

Aside from features and benfits Win7 has over xp , 64 bit performance mainly. The ability to use more than 4gb of ram (outside of using anything above that as a ram drive) but Win7 32bit has the same limitations.
Make sure your motherboard has Win XP drivers available.