Thanks for considering the speedup. Will make it perfect. I double checked my thumbsize, and i AM also using 512 size. Must have forgot i changed it higher from 256. Currently i have an average of 90-100 movies. And after further checking. I noticed that when the icons (especially LIST view.) are mostly blank, my LCD show "Freemem: 0MB" or "1", so it looks like something having to do with caching/running out of memory to check. I think one reason other skins i use don't have this effect is due to some views not showing close to as many icons on screen at once. Like a lot show, guessing from memory, 10-12 icons or so, verses 18 with yours using 'Icons' view.
But when in 3d cover, i notice a random blanked out one or 2 when flipping through, and mem shows 3MB Free. Hope this helps. I could always resort to using 256 for now, which still looks ok i guess. I'm using it on an HDTV 80 16x9 projector display in my theater, and also on my 37inch 16x9 HDTV in my room. (720p on both, 1080i with pictures)
Update- More researching, noticed that in LIST view using xTV, it doesn't show any missing icons, but in your it does, my guess is the difference of that your skin shows big icon on left (like xTV) AND small thumbnail icons next to each title in list, so it's using more memory. (Never drops below 31MB Freemem using list view in xTV, verses 0-1MB in list view with Back-Row) And also, it does also drop 1 or 2 icons as well in xTV in Icon view, just not as many though. Hope that all helps.