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Question about CPUs and cores in general?

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January 16, 2013 8:47:10 AM

Today i was having this debate with my friends about CPUs and clock speed vs cores, and to say the least its left me pretty confused and i dont know whats right or wrong anymore, i was hoping perhaps someone knowledgeable here would clarify things for me? :D 

The first of the 3 said that if a CPU has 4 cores and its clock speed is say 2.7Ghz, then each of them is running at around 600Mhz and that whenever an application requires more processing power the OS will let the application use a second core, that way it evens out the load and balances it not to lockup the system, and operating systems like Windows 7 and Vista allow a demanding program not optimized to use more than one core to use more (generally this is what i thought, its like my mantra for choosing a new processor in a build)

The second of them said that one of the four cores is 2.7Ghz but the other 3 balance it out when rhe first is overloaded, but that the total processing power isnt divided among the cores o.O

The last one said that a if a CPU is a quad core then then first 2 cores run at 2.7Ghz and the other two are used for turbo boosting to increase the clockspeed when needed

ive spent like the past hour searching up an answer to my question but ive just found people either reiterating one of the 3 above ideas but no definitive answer, that or going into the complexities of how processors work or siding with one cpu brand and saying its better, could someone please clarify to me which is true in layman's term? much appreciated :ange: 
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January 16, 2013 8:53:18 AM

Clock speed, cores.. Doesn't really matter anymore. No, the cores don't run at clockspeeds like 600MHz like that, they all individually run at 2.7GHz. No, applications don't use more cores when things get intensive, they use all cores, but as it gets more intensive the CPU workload ramps up & it starts doing more processes. Your second & third friends there are wrong & should learn to google stuff and check their homework.
How this stuff works is the computer sees the processor, quad core at 2.7GHz, and the cores run usually at lower clockspeeds when not under a lot of work. But when an application comes into play, the clockspeed boosts up to 2.7 or what have you, and the application uses all 4 cores to achieve its processes because today, many applications are multithreaded & get better performance from the 4 cores.
Hope I taught your friends something!
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January 16, 2013 9:01:05 AM

im never listening to my friends on hardware advice again... >.>
but hold on, doesnt that mean that in total the CPU's maximum clock speed is 10.8 Ghz when fully utilized? O___O
im not that smart when it comes to this stuff :/ 
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a b à CPUs
January 16, 2013 9:15:19 AM

ChiggyChigChig said:
im never listening to my friends on hardware advice again... >.>
but hold on, doesnt that mean that in total the CPU's maximum clock speed is 10.8 Ghz when fully utilized? O___O
im not that smart when it comes to this stuff :/ 


No, clock speed isn't a measure of how much a processor can ...process. It's the frequency of the internal "clock".

Four clocks running side-by-side are still running at normal time, if that awkward analogy helps.

Clock speed is only useful if you are comparing two processors from the same product line, and because CPU performance is hard to quantify to a consumer. There were Pentium 4s that ran at 4Ghz or so, but would be completely destroyed in performance by a modern single core CPU (if they existed).
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a c 114 à CPUs
January 16, 2013 9:17:47 AM

You don't multiply clock speed by the number of cores, all the cores run at the same frequency so when referring to the frequency of the CPU its just that number.
Otherwise it would make sense that going from a dual to a quad core at the same frequency there would be a doubling in performance, and quite simply there isn't.
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January 16, 2013 9:39:35 AM

Oh, so they run in parallel basically and are completely separate from each other? like as if you have 4 separate processors in 1?

@Rammy i like your analogy man! i think im starting to getting this

@manofchalk so if there isnt much of a performance gain from a dual core to a quad, does that mean that the "set affinity" in the Windows task manager doesnt make it see more of the cores to use? i thought that this is workaround for games that arent specifically designed to use more than one core :?
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a c 114 à CPUs
January 16, 2013 9:43:11 AM

Didnt say that the difference isnt much, just not a doubling.
Don't know the setting your talking about.
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a c 114 à CPUs
January 16, 2013 10:12:26 AM

Huh, didnt know that existed.

Dont know what that's for, cant think of a reason why you would want to limit the performance you can give to a program.
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