More recently, virtually all laptop equipment has 480 Mbit/s Hi-Speed USB 2.0 ports, and most types of peripheral which formerly used a PC Card connection are available for USB or are built-in, making the ExpressCard less necessary than the PC Card was in its day. When the PC Card was introduced, the only other way to connect peripherals to a laptop computer was via RS-232 and parallel ports of limited performance, so it was widely adopted for many peripherals.
PCMCIA devices can be connected to an ExpressCard slot via an adapter.
The ExpressCard FAQ claims lower cost, better scalability, and better integration with motherboard chipset technology than Cardbus. The ExpressCard standard specifies voltages of either 1.5 V or 3.3 V CardBus slots can use 3.3 V or 5.0 V. The ExpressCard has a maximum throughput of 2.5 Gbit/s through PCI Express and 480 Mbit/s through USB 2.0 dedicated for each slot, while all CardBus and PCI devices connected to a computer usually share a total 1.06 Gbit/s bandwidth. The major benefit of the ExpressCard over the PC card is more bandwidth, due to the ExpressCard's direct connection to the system bus over a PCI Express ×1 lane and USB 2.0, while CardBus cards only interface with PCI. The older PC Cards came in 16-bit and the later 32-bit CardBus designs.
