I built this HTPC several months ago (Asus M3A78-EM, Athlon 4850e, ATI Radeon HD 4800 Series video card, 4GB RAM, Windows 7 x32 Professional - MC 14.0.130 at present but has done it since MC13 when I first built this machine) and, through several iterations, the same issue has arisen.
Unlike my other PCs, this one takes ages to build the thumbnails of my ripped movies (.avi, 720p - currently 106 of them) on my Windows Home Server - usually, several days (yes, I said 'days') and even then 2, 3 4 won't succeed. As I say, the four other computers in the house do it in a few seconds but this one is always glacial. Works fine on Audio: 14000+ tracks and that library is built quickly (noting that most of tags include 500 x 500 album covers) but not in relation to Videos.
I've tried swapping the video card, several other things but still this slowness remains. Anyone have any thoughts on where to look? What to try?