Minimum Requirements for Decal 3:

• Windows 2000 or later 
• Asheron's Call, Working properly, and running in hardware 3D mode
• Internet Explorer 6.0+
• Direct3D 9.0c with Extensions (April 2006)
  
• Microsoft .NET Runtime 2.0
• Windows Installer 3.0 

Recommendations:

• Windows XP or later
• Video card with at least 128MB Ram (Alpha build recommendation)
• Avoid Hi-Res textures (Alpha build recommendation)
• Windows Installer 3.1

Comments:

We're recommending that you avoid the new Hi-Res textures unless you have a LOT of video ram, due to currently very high video memory requirements of alpha builds of Decal 3. We've seen HiRes textures work with some 256MB cards, but that was with simple plugins. Complex plugins like ElTank will likely have problems.

If you have a recent video card, make sure antialiasing is off.  Antialiasing causes problems with the way Decal does things at the moment.