Dred, there are now 402 skins in the game. Windows XP does not support enough RAM to have all the skins loaded.
Now, the skins only load when they need to, so it is doubtful you will ever be online long enough, in one session, to actually see all 400+ skins.
However, if you run into a batch of new skins on planes, I could see it causing a heck of a stutter while they load.
The best solution I can give you is to disable the background downloads, and then load only the skins you really want to see. If they are resident on your computer and skins are not disabled, the game will make use of them. If the skin is not present, you get the default one.