spring runs terribly slow when I build units & under att

[MAXDDARK]

I run DebSpring version 0.72c http://fbo.no-ip.org/cgi-bin/twiki/view ... g_for_a_di .
and when I build up some units (40-50 units) the game runs unplayable slow.
I get this in-game error while it slows down "Delayed sync respone from you".
I have P4 1800Mhz , 1GB of RAM and ATI9800 Pro Video Card
I run it on Linux Ubuntu.

the only graphic options I have in DebSpring is resolution which doesn't help very much.

could this error possibly happen due to slow internet connection ? (even if I play single player ???).
what can you suggest me except buying a new PC ?