Mhz and MIPS

[leeroyMarv]

From what I understand it's roughly true that most modern computers can (or do) execute 1 instruction per cycle (IPC), but doesn't that mean that if a computer runs at, say, 3.6 Ghz it would also theoretically run 3.6 Billion Instructions Per Second (IPS), so would it be true or wouldn't it that one hertz or (cycle of the clock) is roughly equivalent to one instruction?
i.e. hertz = IPS

p.s. Forgive me if this question sounds stupid

 

[Geoff]

I dont know too much on the subject, but I dont believe its true. Because if it was, then a Celeron D 2.4Ghz would perform more IPS's then a 1.86Ghz Core 2 Duo (ignoring the fact its a dual-core).

 

[billygt]

Well if it's dual core, each core would do 1,86 billion IPS, so the computer would run 3,72 billion

Forget that, I had'nt seen the "D" after Celeron

 

[Geoff]

Well if it's dual core, each core would do 1,86 billion IPS, so the computer would run 3,72 billion

Forget that, I had'nt seen the "D" after Celeron

Forget multiple cores for a moment.

If that was true, then a Celeron D 2.4 would outperform a Pentium M 1.8. (Celeron D doesnt mean dual-core, just in case you were getting that confused).

 

[leeroyMarv]

Yes, but in a dual core processor each core can run at that speed but each core would be executing its own seperate instructions so you couldn't really deem it twice the speed, i'm not sure if both cores can run at once, because if that were so i suppose it would theoretically process at twice the speed and an xbox 360 doesn't run a 10.8Ghz as i believe it is tri-core and 3.6 gigahertz. Back to the topic, I have heard it said many times that computers do execute 1 instruction per cycle (some can do 1.5), which means theoretically the IPS would have to be equivalent to the hertz, unless perhaps the cycle is referenced to something besides the clock?

 

[Geoff]

Yes, but in a dual core processor each core can run at that speed but each core would be executing its own seperate instructions so you couldn't really deem it twice the speed, i'm not sure if both cores can run at once, because if that were so i suppose it would theoretically process at twice the speed and an xbox 360 doesn't run a 10.8Ghz as i believe it is tri-core and 3.6 gigahertz. Back to the topic, I have heard it said many times that computers do execute 1 instruction per cycle (some can do 1.5), which means theoretically the IPS would have to be equivalent to the hertz, unless perhaps the cycle is referenced to something besides the clock?

The reason you cant add up the processing speed of each core, is because they cant be used on the same process. For instance, say your playing a game on a dual core 2Ghz CPU. The game's process only runs on one core, thereby only using 2Ghz of processing speed.

However if the rumors of AMD's "reverse hyperthreading", were true, then you may be able to add up the clocks because multiple cores would be working on the same process.