I was wondering if this was due to the difference of OS, or in difference of the power of the machine (the Linux box we are currently using is a pretty high powered workhorse, compared to the Windows server)?

Nah, it seems unlike that if one machine is a pretty high powered workhorse compared to the other, that the difference can be explained by the power of the machine.

It's probably smurfs. That's a much more logical explanation.