> Dear list,
> regarding bandwidth consumption,

There are two performance issues here.  One being the drawing speed which rdesktop can actually outperform mstsc.  The other is bandwidth performance in which we can only hope to match mstsc.

Drawing speed
Match the Xserver bpp with the connection bpp.  On x86 clients, the bitmaps don't have to be translated.  I assume you are using all x86 hardware.  For example, run your Xserver at 16bpp and connect with -a 16
Check you Xserver hardware.  rdesktop can only be as fast as the unlying Xserver. Use a well known and tested chipsets.
I see the best performance with 16bpp Xserver with ATI cards connecting with either -a 8 or -a 16 on x86 machine.  Even pentium 1 and 2 machines work well.
Don't use -a 24 unless you have the hardware.

Bandwidth speed
Use the lowest bpp possible.  -z(rdp compression) works with 8bpp server connections.
Use persistant bitmap cache.  -P option.

I wonder if rdesktop matches thinsoft bandwidth with -P -z -a 8 options.  I know you want higher bpp, but I am curious.

A workaround with higher bpp could be setting the server to use low encryption.  The data send from the server to the client(which is the bulk of it) will not be encrypted therefore it can be compressed.  Then run the rdesktop connections over a secure / compressed link like a cisco vpn or ssh.

Good luck