notification output bottleneck

I've never noticed this before (slow server, but now I'm testing a
new, faster server), but it seems that the writing of notification
output on stdout is a bottleneck for checkout, update or export on
Windows (cmd.exe). With a fast server, hot caches, and everything on a
Gb LAN, checkout of a large working copy is twice as fast (from 79
minutes down to 35 minutes) when I redirect output to NUL. I tested
with both 1.7.5 (SlikSVN) and trunk, the results were about the same.

Is there anything that could be done in svn to remove that bottleneck
(buffering, ...)?

(there might have been some discussion about this before, but I can't find it)

-- 
Johan