Cpu Reference Clock - Nvidia nForce 590 SLI User Manual

CPU Reference Clock

CPU reference clock refers to the HyperTransport reference clock signal of the bus
connecting the CPU to NVIDIA nForce 590 SLI SPP chip. Typically, CPU
reference clock frequency is 200 MHz.
Updating the CPU reference clock requires several steps, described in this section:
1. Change system clocks in system BIOS menu.
2. Change memory timings in system BIOS menu.
3. Change system voltages in system BIOS menu.
4. Fine-tune the CPU reference clock in the motherboard settings control panel
of nTune.
5. Text the stability of the system
Because the CPU reference clock value direct impacts CPU core frequency and
HyperTransport bandwidth, take some time to determine the maximum attainable
CPU reference clock. To do so, use the following formulas:
CPU core frequency = CPU reference clock (MHz) × CPU multiplier
HyperTransport bus speed = CPU reference clock (MHz) × HT multiplier
Change System Clocks
Before you can find the maximum CPU reference clock the NVIDIA nForce 590
SLI motherboard is capable of achieving, you must make sure all reasons for
instability in the system are eliminated. Possible causes of instability include
undesirable values for CPU core clock, HyperTransport frequency, and memory
frequency. Make sure these are set well within their specifications in order to isolate
the root cause of issues that may arise from increasing the CPU reference clock
frequency.
When the system shows signs of instability, use the following procedure and the
BIOS menu shown in Figure 3 to reconfigure the system to better isolate the root
cause of issues:
1. Lower the
other AM2 CPUs x5 will work) in
2. Change
3. Set the
the CPU reference clock later using nTune.
DU-02451-001_v01
05/17/06
NVIDIA nForce 590 SLI Technology Chipset Overclocking
to (for FX-62 CPU, this value is sufficient; for
CPU Multiplier x9
System Clocks
CPU <-> nForce SPP multiplier to
to
Ref Clock (HTT) 250 MHz
BIOS menu.
x3 .
as a starting point. You can fine-tune
9