Table 6-1: Pentium II Klamath Specifications
Processor Family Model Name Intel Pentium II Klamath
Performance Rating 233 MHz
Generation Sixth: 80686 IA-32
Operational Rates Level 1 Cache Speed 1.0× Core Rate
Level 2 Cache Speed 0.5× Core Rate
Front-side Bus Speed 66 MHz
Multiplier Ratio 3.5× – 4.5×
Physical Design Interface Packing 242-Pin Slot 1 Cartridge
Core Die Size .28 micron, 203 mm2
Transistor Count 7.5 Million
Voltage Interface Split Core and I/O
Core Voltage 2.8 volts
Design Core TechnologyOOO and Speculative Execution RISC
Maximum Execution Rate 5 Micro-Ops per Cycle
Data Bus Width 64 bit
Maximum Memory
Support Physical = 64 Gigabyte
Virtual = 64 Terabyte
Multi-Processor Support 2-way SMP via APIC
Level 1 Code Cache 16 KB 4-way
Static Branch Prediction Supported
Dynamic Branch 512 Entry 4-way
Table 6-1: Pentium II Klamath Specifications
Processor Family Model Name Intel Pentium II Klamath Prediction
RSB Branch Prediction 4 Entry
Floating-Point Processor Integrated
Multimedia Extensions MMX
Pentium II Klamath 233
Table 6-2: Pentium II Klamath 233 Specifications
Processor Family Model Name Intel Pentium II Klamath
Performance Rating 233 MHz
Front-side Bus Speed 66 MHz
Multiplier Ratio 3.5×
Physical Design Interface Packing 242-Pin Slot 1 Cartridge
Core Die Size .28 micron, 203 mm2
Transistor Count 7.5 Million
Voltage Interface Split Core and I/O
Core Voltage 2.8 volts
Power Consumption 23 watts
Maximum Power 34.8 watts
Table 6-3: Pentium II Klamath 233 Overclocking Pentium II Klamath Model Rating 233 MHz
Overclocking Potential Multiplier Lock Support Unlocked Multiplier
Typical Multiplier O/C Up to 4.0×
Typical Front-side Bus O/C Up to 75 MHz
Typical O/C Potential 266 – 300 MHz
Maximum O/C Potential 300 – 333 MHz
Overclocking
Tolerances Recommended Cooling Type Forced-Air Heatsink Recommended Heatsink Coolers Globalwin VEK 16
Vantec PIID-4535H
Recommended Peltier Active
Cooler STEP-UP-53X2
Maximum Core Voltage
3.0 volts with Heatsink Cooler
Table 6-3: Pentium II Klamath 233 Overclocking Pentium II Klamath Model Rating 233 MHz
Maximum I/O Voltage3.5 volts with Chipset
Cooler
Maximum Core Temperature 72° Celsius
Strategy
The Pentium II 233 is Intel's first entry in the series. As you might expect,
overclocking potential for this processor is limited. The majority of the P2 233 chips in circulation are not multiplier locked. The lack of multiplier locking with the P2 233 is helpful, as most of early Slot I motherboards lack support for frontside bus speeds above 66 MHz. Overclocking can therefore be accomplished by changing the clock multiplier alone.
The simplest way to overclock the Pentium II 233 is to increase the core multiplier value from the default of 3.5× to 4.0×, and thus achieve 266 MHz. Higher speeds may be possible with some configurations, but limitations in the 0.5× cache architecture will maximize returns at 337.5 MHz (83-MHz front-side bus × 4.5 multiplier). The external Level 2 cache chips found with the P2 233 often fail at speeds above 166 MHz. Some users may be tempted to disable the L2 cache to reach higher core speeds, but removing this important buffer will result in serious performance losses, outweighing any benefits.
Pentium II Klamath 266
Table 6-4: Pentium II Klamath 266 Specifications
Processor Family Model Name Intel Pentium II Klamath
Performance Rating 266 MHz
Generation Sixth: 80686 IA-32
Operational Rates Level 1 Cache Speed 1.0× Core Rate
Level 2 Cache Speed 0.5× Core Rate
Front-side Bus Speed 66 MHz
Multiplier Ratio 4.0×
Physical Design Interface Packing 242-Pin Slot 1 Cartridge
Core Die Size .28 micron, 203 mm2
Transistor Count 7.5 Million
Voltage Interface Split Core and I/O
Core Voltage 2.8 volts
Power Consumption 25 watts
Maximum Power 38.2 watts
Table 6-5: Pentium II Klamath 266 Overclocking Pentium II Klamath Model Rating 266 MHz
Overclocking Potential Multiplier Lock Support Unlocked Multiplier
Typical Multiplier O/C Up to 4.5×
Typical Front-side Bus O/C Up to 75 MHz
Typical O/C Potential 300 – 333 MHz
Maximum O/C Potential 333 – 350 MHz
Overclocking
Tolerances Recommended Cooling Type Forced-Air Heatsink Recommended Heatsink Coolers Globalwin VEK 16
Vantec PIID-4535H
Recommended Peltier Active
Cooler STEP-UP-53X2
Maximum Core Voltage
3.0 volts with Heatsink Cooler
Maximum I/O Voltage3.5 volts with Chipset
Cooler
Maximum Core Temperature 73° Celsius
Strategy
The Pentium II Klamath 266 offers overclocking capabilities similar to those of the 233. As the family's second generation, the 266 offers overclocking potential upwards of 350 MHz. Any additional gains are probably attributable to variations in the Level 2 cache memory chips. Intel used various brands and types of these chips in its
Klamath series.
Pentium II Klamath 300
Table 6-6: Pentium II Klamath 300 Specifications
Processor Family Model Name Intel Pentium II Klamath
Performance Rating 300 MHz
Front-side Bus Speed 66 MHz
Multiplier Ratio 4.5×
Physical Design Interface Packing 242-Pin Slot 1 Cartridge
Core Voltage 2.8 volts
Power Consumption 28 watts
Table 6-6: Pentium II Klamath 300 Specifications
Processor Family Model Name Intel Pentium II Klamath
Maximum Power 43.0 watts
Table 6-7: Pentium II Klamath 300 Overclocking Pentium II Klamath Model Rating 300 MHz
Overclocking Potential Multiplier Lock SupportPotentially Unlocked Multiplier
Typical Multiplier O/C Up to 4.5×
Typical Front-side Bus O/C Up to 75 MHz
Typical O/C Potential 333 – 350 MHz
Maximum O/C Potential 350 MHz
Overclocking
Tolerances Recommended Cooling Type Forced-Air Heatsink Recommended Heatsink Coolers Globalwin VEK 16
Vantec PIID-4535H
Recommended Peltier Active
Cooler STEP-UP-53X2
Maximum Core Voltage3.0 volts with Heatsink
Cooler
Maximum I/O Voltage3.5 volts with Chipset
Cooler
Maximum Core Temperature 75° Celsius
Strategy
The Pentium II 300 MHz offers moderate overclocking potential for those lucky
enough to possess a model that is not multiplier locked. Reports have varied over the years since this Klamath model was introduced, but it appears that some units did ship with multiplier-locked cores. Overclocking potential for locked Klamath 300-MHz processors will be limited; increasing the front-side bus beyond 75 MHz is nearly impossible. A front-side bus speed of 83 MHz will result in a core rate of
approximately 374 MHz (83 MHz □ 4.5), a speed often beyond the capability of the .28-micron Klamath core.
Owners of unlocked Pentium II Klamath 300 processors may benefit if an 83 MHz side bus speed is supported by the system's motherboard. Increasing the front-side bus rate to 83 MHz, while decreasing the processor multiplier value to 4.0×, often yields a stable 333 MHz. The increase in frontside bus speed will boost performance significantly: memory and PCI bus rates will also be overclocked. The half-speed Level 2 cache architecture of the P2 limits bandwidth between the
processor and memory subsystems. Therefore, additional bandwidth obtained by overclocking the front-side bus can greatly improve memory performance.