Low RED throughput

Hi,
My remote branch users have been complaining about slow file copy times. I'm only getting 3.2Mbps AGS220->RED and 1.3Mbps RED ->ASG220. The ASG220 has a quad T1 6x6Mbps connection and the RED has a 50x10Mbps cable modem connection. The tests were done between two Windows XP machines. The RED is set up as standard/split so the only traffic going through the RED is just internal network traffic. I know that Windows SMB protocol is pretty crummy, but could it really affect my transfer rate this much? My ASG220 is an older v2 unit with only a 2.8GHz P4 but the CPU usage is only about 15% during the tests. Screenshots...






I've also tested both connections and I'm able to saturate the T1's at 6Mbps and the cable modem speed tests at 38.5x8.7Mbps.

I read the thread below about slow RED transfer rates but I'm not using Bridged mode.

Thanks,
Ben