Does MS SQL ever have a dedicated CPU?

Dear Experts,

I might need to introduce multi-threading to my app.  In my MS SQL shop, our 2000 box has one processer, and our 2003 box has two.  To test multi-threading, I'll need at least two.  But it occured to me that MS SQL itself might have a dedicated processor in this case, and my code would then be restricted to the other CPU.  Is that possible?

Thanks,
BrianMc1958