Connection to Windows 7 horribly slow except when using "-b"

Hello

After upgrading a host from Windows XP to Windows 7 the rdesktop connection
to it became horribly slow. I can see the background image and all application
windows updating as several bitmap tiles. The speed of the applications has
not suffered, only their "drawing speed".

The remote Windows system runs on a Linux KVM virtualisation
system, which should not matter though as a collegues Windows on the same
host is fast as usual.

My desktop from which I start the client has the following specs:
	OS: 		Debian Linux 7 wheezy
	Kernel:		3.13-0.bpo.1-686-pae
	GPU:		NVIDIA Corporation GF119 [GeForce GT 610] (rev a1)
	X11:		/usr/lib/xorg/modules/drivers/nvidia_drv.so
	NVIDIA Kernel:	(II) NVIDIA dlloader X Driver  331.49  Wed Feb 12 19:58:43 PST 2014
	rdesktop:	1.7.1-1

I already played around with the different options and only a switch 
from "-5" to "-4" solved the problem. It had worked with the default
"-5" for WinXP all the years though.

I also compiled the latest rdesktop 1.8.1 from source and tried it.
With the default settings it was also slow but when using the new
"-b" options it got significantly faster!


I am wondering now how to track the problem further down and why you
added this new "-b" option. Is there maybe a known incompatibility
that matches my description?

best regards,

-christian-

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