Well, I don’t use much Graal.
I just tried to launch Graal Clients here, on Windows 8 preview.
I believed they were freshly downloaded versions (copied from my USB key).
That mostly works, but the background fastly become wrong when moving.
Stripes, appears, with repeating patterns.
So mostly making the game not playable.
This happens both in training, and on servers.
I tried the 3 clients: Graal_222, Graal_231, Graal_2171. They all do the same.
The game client was made for windows 98. It uses an early version of directx very poorly. The compability With windows 7 is surprising to say the least. I Had lots of problems With the clients on vista.
It depends on what you call compatibility mode.
Windows compatibility mode does not seems to do any good.
compabilitydraw=true inside graalconfig.txt does seems to fix the problem.
But it makes it quite slow.
I recommend running Windows XP 32bit, Windows 2000 32bit or Windows98SE ran in Virtual Box such as http://www.oracle.com/technetwork/server-storage/virtualbox/downloads/index.html you can find Windows 98SE or XP ISOs on ThePirateBay or many torrent sites and can hook in the ISO file as a virtual drive to set up the OS directly in Virtual Box. Also WINE in Linux will run most of the graal client versions without issue. I also am strongly opposed to having Windows Vista, 7 or 8 as your main OS. I recommend XP Pro x64, Server 2003, or XUbuntu or Mint Linux. You can also set up multiple OSes and select them from a boot menu. Remember for Graal and older programs you want to be running a 32bit version of the OS and running them in VirtualBox makes it extremely convenient and safer.