User guide

NVIDIA nForce 590 SLI Technology Chipset Overclocking
DU-02451-001_v01 15
05/17/06
CPU HyperTransport Overclocking
CPU HyperTransport (HTT) bandwidth (speed) is an important contributing factor
to overall system performance. Its nominal effective bandwidth is 4 GBps running
at 1 GHz (200 MHz × 5) upstream and downstream. CPU HTT bandwidth is
directly proportional to CPU reference clock as mentioned earlier in CPU Reference
Clock on page 9. It defines how fast data propagates between PC devices and CPU
and system memory to maximize throughput. Furthermore, CPU HTT bus speed
has a tremendous impact on memory performance.
Use the following procedure to overclock CPU HyperTransport bandwidth:
1. Eliminate all sources of instability by configuring
System Clocks BIOS
settings as shown in Figure 8.
a) Lower the
CPU Multiplier to x10 (for FX-62 CPU, this value is sufficient
and to be safe a x8 multiplier will work; for other AM2 CPUs x5 will
work) in System Clocks BIOS menu.
b) Change
CPU <-> nForce SPP multiplier to x5.
c) Set the
Ref Clock (HTT) to 200 MHz as a starting point. You can fine-
tune the CPU reference clock later using nTune.
Figure 8. System Clocks BIOS Configuration for CPU HTT
Overclocking
Note: In the Memory Timings BIOS menu, make sure Memory Clock Limit is set
to [DDR2 400] as shown in Figure 4.