I have FINALLY figured out how to get the SP13000 to do the 800x480
You will need this:
http://www.via.com.tw/en/products/ma.../downloads.jsp
Download the latest BIOS and flash utilty.
Now the fun part............
You need to make a bootable CD and inlcude on it the Flash and Bios.....
This is what I did.....
you need this....
http://www.nu2.nu/download.php?sFile=bbie10.zip
Goto the website listed in the link to get directions....
extract the boot information from a bootable cd....you are on your own here....
Now you need Record now from Roxio or equivilent.....
Create a Boot CD in your CD burning program and add the Flash and Bin program to the CD as well.
Boot the system and run the flash utility.....
It will not allow you to save the old Bios.....no biggie.
When done reboot and WALA...........you now have 800x480 and it looks REALLY sharp....
It fixed alot of problems I was having with video in MCE2005.......
Hope this helps......