Direct Cache Access
From Intel Application Note 485, "Intel Processor Identification and the CPUID Instruction", section 3.1.10:
When EAX is initialized to a value of 9, the CPUID instruction returns DCA information in the EAX, EBX, ECX and EDX registers:
- EAX: Value of PLATFORM_DCA_CAP MSR Bits [31:0] (Offset 1F8h)
- EBX: Reserved
- ECX: Reserved
- EDX: Reserved
I've got a list of DCA-enabled NICs.
DCA requires both hardware and software support. Its successor, DDIO, does not.