Quote Originally Posted by ritaheed View Post
Can someone explain the need for 4 X a 3.2ghz i7 processor in a single computer.

From what ive been told this doesnt make the comp run at over 13ghz but only at 3.2ghz

Anyone wanna explain the need, benefits etc
No, multi-core isn't as simple as "times the speed by the number of processor cores"
It's also made worse by the actual speed of the core isn't the speed of how many instructions it can process per second, because each processor core has multiple pipes and can process multiple independent instructions. It also goes the other way where you can have processing stalls due to instruction dependencies. Basically the processing speed isn't linear at all.

My very rough rule of thumb and it's probably wrong since I last looked, is the efficiency of a processor core in comparison to its paired cores is like this;

First core = 100% processing
Second core = 80% processing of first core
Third core = 80% processing of second core
etc.

This is due to the instructions having to be routed to the relevant processor core, plus all the cores have to access the same RAM, etc. So you've got transfer stalls there also. Probably take 20% from overall for that.

You've also got to consider that cores are normally controlled by software, so if the software doesn't use the cores properly, the performance will stink.

Truth is if each core was 3GHz and you had four of them, I wouldn't expect it to perform much better than a 5GHz single chip.


TBH tho', I've never really had a problem with 1.xGHz as a standard desktop machine for coding, audio and graphics. But then I don't use my machine for gaming and that is literally the only thing it doesn't do.