UNIX for Dummies Questions & Answers

Hello all ,
This is the output of my prtdiag command ...The speed of each of the CPUs is listed below (1281 MHz ) ..That's fine ..I'm confused about the (System clock frequency: 183 MHZ ) ..What is the difference between System Clock freq and CPU freq ...THanks..

System Configuration: Sun Microsystems sun4u Sun Fire V440
System clock frequency: 183 MHZ
Memory size: 16GB

==================================== CPUs ====================================
E$ CPU CPU Temperature
CPU Freq Size Implementation Mask Die Amb. Status
Location
--- -------- ---------- --------------------- ----- ---- ---- ------

0 1281 MHz 1MB SUNW,UltraSPARC-IIIi 2.4 - - online
1 1281 MHz 1MB SUNW,UltraSPARC-IIIi 2.4 - - online
2 1281 MHz 1MB SUNW,UltraSPARC-IIIi 2.4 - - online
3 1281 MHz 1MB SUNW,UltraSPARC-IIIi 2.4 - - online

The system clock sends out signals to keep everything in sync. The cpu frequency is how fast the cpu can do stuff. Your cpu frequency is 1281 Mhz and your system clock is 183 Mhz. Note that 183 * 7 = 1281. The CPU will keep its clock synced up to the system clock. All of the clocks in your system will be created by multiplying or dividing the system clock by some small integer. The cpu's all plug into a bus. And memory plugs into the same bus. This bus almost always runs at the system clock rate.

CPU multiplier
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The CPU multiplier is one way for processors to run much faster than the clock speed that the motherboard or RAM allows. For every tick of the front side bus (FSB) clock, a frequency multiplier causes the CPU to perform x cycles, where x is the multiplier.

So, for example, if the FSB has a clock speed of 133 MHz and the CPU multiplier is 10x, then the processor would run at 1.33GHz. This means a processor can be run much much faster without having to increase RAM speeds or motherboard speeds and worry about desyncs, or other speed related issues.

The CPU multiplier is frequently used by PC enthusiasts to overclock a CPU to get somewhat higher performance from it.

One downside of the multiplier is it only increases CPU speed. In the previous example there is a multiplier of 10x, but RAM still runs at 133 MHz, so the computer can only access memory at 1/10th of the processor speed, 133 MHz, the speed of the FSB. Because of this, many overclockers prefer to have lower multipliers with higher FSBes.

Whats odd is you have IIIi 2.4's in there it looks like...Why are they running at half speed? Is that something with power management? Oh haha that is CPU Mask DUH nvm.... I should have noticed that anyway because I believe 1.5gig is as high as IIIi's go.

First, I don't believe that the 2.4 in CPU's nomenclature is an indication of speed. I do not see any indication that Sun supports any higher speed for it.

As for cranking up the multiplier, most CPU's spend a lot of time waiting for the bus anyway. That is why hyperthreading works. But my laptop does have a programmable multiplier. The idea is the the CPU runs slow until idle time drops. Then it speeds up. Intel calls this SpeedStep. I have only seen this sort of thing on laptops to prolong battery life.

Thanks to all for your valuable input ...