Template:mpu K6-2/400ACK-66 was a 32-bit x86 K6-2-based mobile microprocessor designed and manufactured in 1999 by AMD. Manufactured using a 0.25 µm process, this MPU operated at 400 MHz with a FSB operating at 66 MHz. Note that K6-2/400ACK is an identical version with a bus speed of 66 MHz instead of 100.