Parameters of Chipset and Buses Overclocking. Part I

It is possible to improve the productivity of chipset and buses by increasing their frequencies. But it is quite common that you have to set fixed values of these frequencies to avoid their excessive raise during the processor overclocking.

НТ Frequency (LDT Frequency, НТ Link Speed)

This parameter changes the frequency of HT (Hyper Transport) bus through which the AMD processors and chipset are exchanging the data. The multipliers can be used as values of this parameter, and to calculate the actual frequency you have to multiply a chosen multiplier by the value of a base frequency (200 MHz). In some version of BIOS you have to choose a frequency of the HT bus from several available values.

A maximum HT frequency for the Athlon 64 processors was equal to 800-1000 MHz (a multiplier 4 or 5) and for the Athlon П/Phenom II processors – 1800-2000 MHz (a multiplier 9 or 10). During overclocking a multiplier for the HT bus should be sometimes decreased in order to the HT frequency does not go beyond the permitted limits after the base frequency rise.

AGP/PCI Clock

This parameter sets frequencies for the AGP and PCI buses.

Possible values:

  • Auto – frequencies are selected automatically;
  • 66/33.33, 72.73/36.36, 80.00/40.00 – the frequency of the AGP and PCI buses accordingly. A standard value is 66.66/33.33, the others may be used while overclocking.

PCIE Clock (PCI Express Frequency (MHz))

This parameter allows modifying a frequency of the PCI Express bus manually.

Possible values:

  • Auto – a standard value is set (usually 100 MHz);
  • from 90 to 150 MHz – a frequency can be set manually and the range adjustment depends on the motherboard model.

CPU Clock Skew (MCH/ICH Clock Skew)

These parameters allow regulating a shift of clock signals (CPU) and also northern (MCH) and southern (ICH) bridges.

Possible values:

  • Normal – an optimal value will be set automatically (it is recommended for a normal operation mode and moderate overclocking;
  • from 50 to 750 – a shift size of clock signals in picoseconds. Selection of this parameter may improve the system stability while overclocking.