ASUS P4B533-V Serial Port Modem Issues

[GaryUK24]

Not sure if anyone can help, my problem is that when i dial up to my ISP the connection is fine, but the transfer of data is very slow. Although the modem reports 52k connection (what its always been), the Connection Status box in WinXP shows alot of errors in the revcieved data section. This modem worked fine before i ungraded my system with the ASUS board. I have tried the modem in another WinXP system and it works fine on the same line. Therefore the only thing i can think of is the serial port is not working right. I have tried different serial cables and the problem still exists. Baud rate on the port is set to 115200 and hardware flow control is on. Can anyone help???!!!! By the way i have tried two motherboards (RMA'd the first one) and the problem still exists.

System:
Intel P4 2.533Ghz - Thermaltake Volcano 7+
512 DDR (Corsair XMS 3200)
ASUS P4B533-V
GeForce 3 AGP
40 GB IBM 60GXP
30 GB IBM 75GXP
Creative Audidgy
Realmagic Hollywood+ DVD Decoder
Promise 100TX IDE Card
Plextor 24x10x40 CDR/W
Creative 8X DVD
Asus 40X Cd-rom Drive
Antec 1030 Case
Enermax 430Watt PSU
4x Case fans(2 in, 2 out)

MODEM = US ROBOTICS (3com) 56k Voice Fax Modem External serial connection.

Lastest Intel Chipset drivers + Application Accl 2.2
Clean Install of Windows XP Home
Latest Modem Drivers
No IRQ conflicts for anything including serial ports
Parallel port is disabled
On board Sound and Video Disabled.


Thanks In Advance!