I have a handful of pci cards but they only transmit at 14.4. I'm starting to receive enough faxes at home that the price for efax is just unrealistic for a few hundred pages of transmission and receiving per week.
Here are what I see on newegg with 33.6 fax speed:
Newegg.com - MultiTech MT9234ZPX-PCIE-NV PCI Express Data/Fax Modem Newegg.com - MultiTech MT9234ZPX-PCIE 56Kbps PCI Express V.92 Voice/Data/Fax World Modem Newegg.com - MultiTech MultiModem ZPX MT9234ZPX-UPCI-NV 56Kbps PCI Internal Modem
A couple others dont specify whether they max out at 33.6 or 14.4, but none of the lower priced cards seem to support the faster speed. I have space on my main tower for an additional pcie or pci card.