Socket 775 CPUs are the first developed by Intel processors with contact surfaces instead of contact pins. It involves the LGA design (Land Grid Array). This socket type was introduced on the market for the first time in 2004. There are a number of CPUs that hold this type of socket. Among them are the Intel Pentium 4, Intel Pentium 4 EE, Intel Pentium D, Intel Pentium EE, Intel Celeron, Intel Core 2 Duo, Intel Core 2 Quad, Intel Core 2 EE and the Intel Xeon. Socket 775 supports clock frequencies up to 3.8 GHz. Technical innovations were, for example, support for DDR2 SDRAM, PCIe slots and DDR3 SDRAM. In addition, the memory controller is no longer integrated in the processor itself, but on the chipset. was replaced the Socket 775 of Socket 1156 for desktop PCs (2009) and Socket 1366 for servers (2008).