The PXA25x family (code-named Cotulla) consists of the PXA250 and PXA255. The PXA250 was Intel's first generation of XScale processors. There was a choice of three clock speeds: 200 MHz, 300 MHz and 400 MHz. It came out in February 2002. In March 2003, the revision C0 of the PXA250 was renamed to PXA255. The main differences were a doubled internal bus speed (100 MHz to 200 MHz) for faster data transfer, lower core voltage (only 1.3 V at 400 MHz) for lower power consumption and writeback functionality for the data cache, the lack of which had severely impaired performance on the PXA250.