Originally Posted by Aryan1171
Hey guys, this question has been haunting me for several years now..
Why do cpu's use multipliers. i mean isn't it easier to just
raise the clock of the cpu to the desires speed?
In stead of that you get a speed of let's say 133 mhz x 10.
Isn't it better to just take the first? Is it because of heat or
something, because I can find everything about the multiplier it self on wikipedia, just not WHY.
Also, what does this say to you?
I'm still learning, but my basic understanding (so far) of the introduction of CPU multipliers leads me to this explanation:
In early motherboards, the clock chip ran all mobo chips at the same speed as the CPU. After a while they found that CPUs could run much faster than the other chips on the board and came up with clock-multiplying CPUs to allow their speed to rise without affecting the rest of the motherboard. The additional processing that happens during these extra clock cycles and the data created is moved back and forth in the caches - not sent out on external buses until they are ready.
So - now we have 2 speeds to think about, the internal CPU speed and
then the speed at which it communicates with the address & external busses. The first multiplier was only 2x. If they didn't start using multipliers we'd be using much slower computers today.
Nowadays when a CPU needs to run faster, we have the technology to increase its speed using really high multipliers. For example - the Ivy Bridge has a model that uses a 45x multiplier on 100MHz - imagine all
the motherboard chips having to deal with running at 4,500MHz instead of at 100MHz?
The motherboards we buy today certainly woulldn't be priced as low as $200 for an X79. The modern CPU is expensive considering that it is but a single chip - but it has much higher stresses and capabilities than all the other chips on a motherboard. If the others ran at the same exact speed they'd all need massive chip coolers as well!
It's an entertaining thought to try to picture such a thing - you'd be needing such a huge case to hold it and the cooling required would be astonishing. A complete redesign of all the components would be needed - and established industry standards would have to go out the window. Also - depending on what MHz CPU you wanted, all your components would need to handle it.
Thankfully, if you have the desire to increase your CPU speed today on an overclockable CPU you are only affecting it, not the rest of your system
- and everything works out just fine!
HTH...Edited by stratosrally - 8/9/12 at 9:16am