Figure 1, presented above shows all the available clock/voltage tuning options available in the AMD OverDrive™ utility. The processor, northbri dge, PCIe and memory can all be adjusted to obtain an optimally tuned system.
Detailed description of Figure 1 (AMD OverDrive utility screenshot):
Current clock speeds (1)
This section offers
Target clock speeds (1)
The values under this section are calculated based on the clock sliders. It is a convenient way to see the target clock speeds before actually applying the settings.
CPU Multiplier (2)
The sliders in this section control the CPU multiplier. In the case of AMD
The sliders adjust the CPU multiplier of the base frequency (P0). If the AMD Turbo Core technology feature is enabled the multiplier range will be limited to the AMD Turbo Core clock multiplier. Disabling the Turbo Core will extend the range.
HyperTransport™ (HT) reference clock (3)
Almost all the clocks are based on the HT reference clock (200MHz by default). Therefore adjusting the HT reference clock will increase the clock speed of most key components in the system. This includes CPU core clock, CPU NB clock (Memory controller), Memory clock and HT clock frequency. Again, please refer to the “Target Speed” section before actually applying the HT reference clock adjustment. In many cases the HT reference clock margin can be limited by the System Memory clock. If this is the case, it is a good idea to adjust the System Memory settings to a lower value from the System BIOS [e.g. adjust Memclk mode from
HyperTransport™ (HT) Link multiplier (3)
This item can be used to adjust the HT Link multiplier value.
The range of HT Link multiplier depends on the CPU capabilities: with HT1 generation CPU the slider can only go up to X5 (1GHz mode), with HT3 generation of CPUs it can go up to X13 (2.6GHz mode). If HT3 CPU is booted up in HT1 mode (e.g. X5 or lower HT Link multiplier) it cannot be adjusted to HT3 mode on the fly. Switching from HT1 to HT3 mode requires a BIOS adjustment. In most cases it is best to adjust the HT Link multiplier from the BIOS.
PCIe® Speed (5 )
This item controls the PCIe® clock frequency of the PCIe® graphics slots. By default this value is 100MHz. Increasing this value can provide slightly improved 3D performance.
CPU Core voltage adjustment (5)
This item can have two sliders: CPU VID and CPU VDDC. The amount of sliders depends on the motherboard that is being used. The CPU VID value is limited to max VID value (1.55V for instance) supported by the CPU. CPU VDDC (or CPU Vcore Offset) slider can be used to adjust the CPU Vcore above the max VID value.
NOTE: If VID OVERRIDE (or “manual mode”) has been enabled from the BIOS the VID sliders have no impact on actual voltage level.
NOTE2: The CPU VID slider has no impact on the voltage that is applied in Turbo Core clock modes. This slider adjusts the voltage of the base frequency mode (P0). The range of the slider is limited to the Turbo Core mode voltage value. Disabling Turbo Core will extend the range to the maximum supported VID value (1.550V in the case of the AMD
Boosting the CPU Vcore voltage can improve the performance tuning headroom of the CPU Core.
PLEASE NOTE THAT CPU POWER AND THERMAL REQUIREMENTS INCREASE EXPONENTIALLY WHEN THE VOLTAGE IS INCREASED. VOLTAGE ADJUSTMENT IS ALWAYS A RISK AND CAN DAMAGE THE HARDWARE AND / OR SHORTEN THE LIFESPAN OF THE CPU OR OTHER COMPONENTS.
System Memory voltage adjustment (5)
This item can also have two sliders (depending on the motherboard that is being used). “Memory VDDQ” (memory core voltage) that defaults to 1.5V is the slider that should be adjusted in most cases. The other slider (Memory VTT) will adjust automatically according to the VDDQ slider adjustment. Normally the VTT level should be 50% of VDDQ level.
Boosting the memory voltage can improve System memory performance tuning.
PLEASE KEEP IN MIND THAT MEMORY VOLTAGE ADJUSTMENT CAN DESTROY NOT ONLY THE MEMORY BUT ALSO THE CPU AND CAN
Chipset voltage controls (5)
There are several voltage rails connected to the AMD 9- series chipset. The PCIe® bus, HyperTransport™ link and Chipset core all have separate voltage rails and controls. Boosting these voltage levels can result in improved performance tuning margin for these interfaces. For an example, boosting the HyperTransport™ link voltage by 0.1V can enable higher HT Link frequencies.
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