Overclocking
PII
Overclocking Basics of CPU
Setting CPU speed
Memory
SDram
RegSDram
Memory market Memory guide
|
|
Optimal Speed for Your CPU
Remember, just because your neighbor or brother or whoever can achieve a certain speed
with their identical CPU doesn't mean that yours should be able to hit that same level.
Each and every CPU is unique. Considering these small cores have 8 million trace routes,
it should come as no surprise that no two CPU cores behave the same under stress. In
addition, the Level 2 cache, which operates at approximately one half the speed of the
CPU, is matched by Intel to the speed of the CPU core to which it is connected. There's
usually a good deal of leeway, but the individual speed of your cache is a key limiting
factor in overclocking your CPU.
The goal of overclocking is to find your CPU's comfort zone--the speed at which it will
run reliably, without system errors or data corruption. Here are some common, relatively
conservative settings.
Pentium IIs With Default 66
MHz FSB (233 MHz to 333 MHz)
233-MHz and 266-MHz Pentium IIs
| Overclocked Speed |
Clock Multiplier |
FSB Speed |
Chipset |
| 300 MHz |
4.0 |
75 MHz |
440LX |
| 300 MHz |
3.0 |
100 MHz |
440BX |
| 336 MHz |
3.0 |
112 MHz |
440BX |
300-MHz Pentium II
| Overclocked Speed |
Clock Multiplier |
FSB Speed |
Chipset |
| 338 MHz |
4.5 |
75 MHz |
440LX |
| 350 MHz |
3.5 |
100 MHz |
440BX |
| 392 MHz |
3.5 |
112 MHz |
440BX |
| 400 MHz |
4.0 |
100 MHz |
440BX |
333-MHz Pentium II
| Overclocked Speed |
Clock Multiplier |
FSB Speed |
Chipset |
| 350 MHz |
3.5 |
100 MHz |
440BX |
| 375 MHz |
5.0 |
75 MHz |
440BX |
| 392 MHz |
3.5 |
112 MHz |
440BX |
| 400 MHz |
4.0 |
100 MHz |
440BX |
Note: To run reliably at a 100-MHz FSB, you need to have 100-MHz SDRAM installed in
your system. Also note that in many of the cases listed above, increasing the FSB speed
requires you to lower the clock multiplier on your system.
Pentium IIs With Default 100-MHz FSB (350 MHz to 450
MHz)
Since August 1998, Intel has been locking the clock multiplier on its CPUs, so it
probably will not be possible to change the multiplier when overclocking a 350-MHz,
400-MHz, or 450-MHz Pentium II. If you try, the CPU will either refuse to boot the
machine, or it will boot it up at 1/3 its proper speed. To get around this limitation, a
Pentium II overclocker's only remaining option is to increase the speed of the frontside
bus.
| Default Clock
Speed |
Default Clock
Multiplier |
Overclocked
FSB Speed |
Overclocked
CPU Speed |
| 350 MHz |
3.5x |
112 MHz |
392 MHz |
| 400 MHz |
4x |
112 MHz |
448 MHz |
| 450 MHz |
4.5x |
112 MHz |
504 MHz |
Danger of Increasing FSB
Speed
Increasing the speed of the FSB also increases the speed of the PCI and AGP buses so
errors might result from some older components refusing to run properly at the higher bus
speeds. For instance, overclocking from 100-MHz FSB to 112 MHz results in the PCI bus
being overclocked to 37 MHz (instead of 33 MHz), and the AGP bus being overclocked to 74
MHz (instead of 66 MHz). Because newer PCI and AGP cards are being designed with greater
tolerances, however, this is becoming less of a problem.
Setting the CPU speed
|