ICS Client speed half the speed of host

I have 3 w2k machines networked via ICS. The host ICS machine uses 1 satelite internet access. The upload modem speed is extremely slow due to local infrastructure an gets a max connection of about 26.4bk. The satelite download connection is usually400-500kb and can peak to about 800kb at times. The ICS clients, though, never gets higher than about 250kb.

Are there any tweaks that can be done to improve the clients? I have tried playing with MTU settings etc with no luck.

Thx