First of all, the PCH is the "chipset" for your system. It is essentially the master I/O controller for your system. With the exception of of the PCIe lanes for graphics (and perhaps a secondary PCIe connector or two) that come directly out of the processor, everything else comes from or goes through the PCH -- USB, SATA, LAN, AUDIO, other PCI/PCIe lanes, the LPC bus, the SPI bus, etc. and etc. and etc. If your PCH is not working properly, your system is likely not going to run at anywhere near peak efficiency either.
Seeing a PCH failure could be an indication of a true H/W failure or it could simply be a driver issue. Are you sure that you have all of the related drivers installed -- and specifically the Intel Chipset Software (formerly "INF Update") package? If it is a H/W issue, it is usually not the processor; it is usually an issue on the motherboard.
Hope this helps,