compacting on XP slow

I have no idea what can cause this, but when I try compact folders when TB is sticked to an XP, it takes ages! Kind of 20 minutes for example.

Tha same job is done on an very slow laptop with w2k in seconds, on w98 similar even the usb port there is just 1.1 and all otherwise slow due to lack of ram.

Why does it take so long on the XP?