I/O Acceleration Technology (I/OAT) is a DMA engine by Intel bundled with high-end server motherboards, that offloads memory copies from the main processor. It's typically used for accelerating network traffic, but supports any kind of copies.
Using I/OAT for network acceleration is supported by Microsoft Windows since the release of Scalable Networking Pack for Windows Server 2003 SP1 [1] and by the Linux kernel since 2006.[2]