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Glossary of Terms
HyperTransport™ Refer ence Clock (HT ref. clk): The base clock for various clock domains on the AMD
“Scorpius” platform technology. HT ref. clock is 200M Hz by default. CPU, CPU NB, HT Link and Memor y clocks
are all linked to HT ref. clock. HT ref. clock adjustment is a g ood tool for fine tuning the various clocks to optimal
values. The HT ref. clock value itself doesn’t have any impact on performance.
CPU: Central Processing Unit – the engine of the AMD “Scorpius” platform technology. CPU core clock
frequency has the biggest impact on overall performance of the system. It’s the primary target of tuning.
CPU NB: CPU NorthBridge (should not be confused with NorthBr idge chipset, such as the AMD 990FX chipset)
– part of the CPU that has it s own clock domain and voltage plane. CPU NB clock frequency determines the
Memory controller and L3 cache speed. CPU NB has a notable impact on overall system perfor mance.
CPU FID: CPU Core Clock multiplier. In the case of the FX-815 0 CPU, the default, base-level CPU mu ltiplier is
x18 (18x200MHz = 3 600MHz). CPU Multiplier can be adjusted on the fly with AMD Ov erDrive™ utility in steps
of 0.5x. CPU Multiplier is unlocked on all of the AMD FX-series CPUs.
CPU NB FID: CPU NB Cloc k Multiplier. Determines the CPU NB frequency. In the case of the AMD FX-8150
CPU, the default value is x11 (11x200MHz = 2200MHz). CPU NB Multiplier adjustment requires a reboot (it can
not be adjusted on the fly). Can be ad justed in steps of x1. Note that CPU NB clock should be 2x Memory clock
or higher (e.g. DDR3-2400 (120 0MHz) would require at least 2400MHz CPU NB clock). CPU NB Multiplier is
unlocked on all of the AMD FX-series CPUs.
HT Link Multiplier: This multiplier det ermines the clock speed of the H T Link. In the case of the AMD FX-8150
CPU, the default val ue is x13 (13x200MHz = 2600MHz). In most cases a reboot is required for HT Link
Multiplier value adjustment. The maximum value of HT Link Multiplier is x13. HT Link Multiplier is unlocked on
all of the AMD FX-series CPUs.
CPU VID: CPU Voltage Identification Digit al – a register value that programs the motherboard voltage regulator
(VR) to a specific value. In short, the CPU VID determines the CP U Core Voltage level. In the case of the AMD
FX-8150BE CPU, the default CPU base clock VID is usually from 1.250V to 1.350V. The Maximum CPU VID
value is 1.550V. NOT E: VID value may not always equal to the actual voltage level (see “Voltage
OFFSET”). VID value can be adjusted on the fly with AMD OverDrive utility.
CPU NB VID: CPU Voltage Identification Digital – a register value that programs the motherboard voltage
regulator (VR) to a specific value. In short, the CPU N B VID determines the CPU NB Core Voltage level. In the
case of the AMD FX-8150BE CPU the default CPU NB VID is usually 1.10 0V. The Maximum CPU NB VID
value is 1.550V. NOT E: VID value may not always equal to the actual voltage level (see “Voltage
OFFSET”). VID value can be adjusted on the fly with the AMD OverDrive™ utility.