Depends on your line conditions mostly. All you can do: ask your telco to come along and measure them.
Maybe another type of modem (a 'hard' modem) is able to squeeze out some more Kb, but don't count on it. So be sure you can return it if it isn't better.
I am using Win XP and am having problems with slow connect speeds of no greater that 45.2 Kbps.
I have the latest modem drivers and am using a PCI SoftV92 Data Fax Modem. (SoftK56V_B2.1_V7.12.01)
I am looking for ideas on how to improve the connect speed.