We have Remote Desktop Session Host farm (formal terminal server). And we had some issues with RemoteFX.

We followed all the right instructions that could be found at: http://technet.microsoft.com/en-us/library/ff817578(v=ws.10).aspx

But still RemoteFX was not working the way we think it should work!

Basic steps to enable RemoteFX in you environment:

• Enable the GPO (see technet link)
• Required MSTSC options

  

According to Microsoft this is all you need to do. This will activate RemoteFX!

I can tell you, IT’S NOT!!!

For Windows 2008 R2 you have to change:

 

For windows 2012 R2:

The color depth cannot be set in the GUI

According to Microsoft windows 8 and higher always uses 32-bit color depth. But you can force it by using a policy:
Computer Configuration\Policies\Administrative Templates\Windows Components\Remote Desktop Services\Remote Desktop Session Host\Remote Session Environment\Limit maximum color depth