The list is loaded from a cache file on disk, xmcache.ini.. after that, it remains in memory and is only written back to disk when closing RR.
I'm assuming that you're complaining about the time it takes to update the currently VIEWED stations with artist/title information.. well, this is a limitation of the XMD receiver -- should virtually be the same speed on any computer. Also, I should remind you that NO XM RECEIVER in the market (as far as I know) is able to do the same feature -- list artist/title info from stations other than the one currently tuned. As far as software goes, there only a handful of them that can do that.. the way RR updates XM info has been discussed a few times, so you can search for that..
There's no feature to "hide" the channels you don't want to see, BUT, you can make favorites lists, that will show only the channels you select/add to them. The functionality you seem to be looking for (both with listing channels and hide channels), is something you'll find right off the box with FrodoXM -- which you can easily run from RR.