I recently upgraded my system, so I had to change my
USR ISA modem to a USR OEM PCI model #2976 (not a
winmodem).
With the ISA modem, I could normally connect to my
ISP at 48K-52K. However, using the PCI modem I cannot
get nothing better than 36K, in the same phone line and
to the same ISP.
Any hints to what I could do to improve the connection
speed ? (I've already checked the output of ati6 and
ati11, and the error/BLER rates seem within acceptable
limits)

Wesley

Try the USR Modem Upgrade Wizard to see if an update is available for the PCI modem.

*DO NOT* update the old modem: there may be a later version for it that will give you the same poor connect rate as your new PCI modem....!