In the PCI-983 ATM OC-3 controller, on-board intelligence off-loads host processing and increases PCI bandwidth utilization. The 64-bit controller can run high-level ATM protocol stacks that reduce the host processor’s I/O workload in voice, video and data communication applications. The board’s high-bandwidth architecture opens I/O bottlenecks and provides simultaneous full bandwidth for the 155-Mbps ATM port. Its ATM SAR controller operates out of local memory, which allows higher-speed transfers to take place on the host PCI bus. The ATM SAR performs memory reads and writes in the 48-byte payload of the ATM cells. By directing these transfers to a local memory, complete packets can be DMA-transferred to host memory from the local memory in large bursts, thus increasing available host-memory bandwidth.