Speed restriction

Hi all,
     I recently bought a new laptop(Acer 3503WLMi) which has a winmodem
built in. I got this working easily under Gentoo using the free license
and could happily connect and download at 14.4K. Then someone gave me a
PCMCIA modem(PSion Gold Card) so I thought I'd make use of this. The
problem is that this modem is also limited to downloading at 14.4(It
connects at 46Kbps but throughput never goes much above 1KB/sec). I've
checked the modem under Windows(cough SPit!) on the same line ringing
the same ISP downloading the same file from my own server and it happily
trundles along at ~4.5KB/sec. This was on three seperate occasions. I've
removed the hsfmodem package and even re-emerged ppp but there seems to
be a hangover somewhere. Can anyone give me a clue as to what could be
wrong?

Cheers

ian