# What does the Hz mean?



## MusicTech

Despite my searches, I have a feeling someone will tell me someone already posted it. What does the Hertz of a processor actually mean, like I have a 2.16 GHz processor, which is fast (enough for me) and all, but so what it oscillates 2160000 times a second, what does that actually do in the way of transferring data? THanks, sorry for such a newbie question.


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## brian

yeah it means that it processes 2,160,000,000 bits (1 or 0's) a secound.


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## fade2green514

http://en.wikipedia.org/wiki/Hertz




> Computing
> 
> In computing, most central processing units (CPU) are labeled in terms of their clock speed expressed in megahertz or gigahertz (109 hertz). This number refers to the frequency of the CPU's master clock signal ("clock speed"). This signal is simply an electrical voltage which changes from low to high and back again at regular intervals. Hertz has become the primary unit of measurement used by the general populace to determine the speed of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark.[4] For home-based personal computers, the CPU has ranged from approximately 1 megahertz in the late 1970s (Atari, Commodore, Apple computers) to nearly 4 GHz in the present. This can be increased even further by increasing the frequency of the CPU (overclocking) in the BIOS or other software. (Likewise, speed can also be decreased, or underclocked.)
> 
> Various computer buses, such as memory buses connecting the CPU and system random access memory (RAM), also transfer data using clock signals operating at different frequencies in the megahertz ranges (for modern products).



so, mhz = millions of cycles per second (1mhz at the bottom range) and ghz = billions of cycles per second (i think one guy got an e8600 to 5.8ghz or something before).

it has nothing to do with data transfer, but with data processing. different processors process at different speeds. for instance, a pentium 4 at 3ghz (with hyperthreading) might perform as much work as a core 2 duo does at 2ghz. the cpu takes different steps to come up with an answer, the core 2 duo just takes less cycles to come up with its answer than the pentium 4.

what has been interesting to me lately is using video cards for processing normal applications.. for instance folding @ home. i really notice an enourmous difference when i switched to using my video card. 

i tried running 3 of my processor cores (since the GPU application uses one up) and it took literally over a day to complete a work unit whereas my video card would finish a few work units in less than a day. its really amazing. if you consider my video card has 800 stream processors clocked at 700mhz (overclocked) thats 560,000 mhz added up whereas 3 of my processor cores adds up to only around 9,000 mhz... 

of course, thats not exactly how it works because of the whole performance per clock thing, but you get the idea lol...


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## MusicTech

Yeah I knew giga was a billion, that was just a typo, sorry.

Ok, cool thanks, that helps a lot. I really appreciate it.


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## sandlotje89

So why are we not at PHz (Petahertz) yet? -- or even close to it?  Have proc companies and researchers lost interest in the speed and gone to researching and producing more cores?

I'm sure that procs at the PHz level would change a lot of things about computing.


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## Vipernitrox

they've hit somewhat of a blockade. called heat, the faster they get the hotter they get. the cooling systems we use still have their limits. And because 2 cores of 2ghz produce much less heat then 1 core on 4ghz for example. They started to research less heat demanding options to increase cpu speeds.


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## fade2green514

yep that's pretty much it. specifically, intel keeps finding newer ways to make a processor with a balanced amount of work per clock (pentium 4 vs. core 2 duo) and a balanced amount of heat versus clockspeed. 

the first processor i ever owned was the last type of micro-processor that was ever produced... 130 nanometer technology was used... or 1.3 micron. it produced quite a bit of heat and it was clocked at 2.2ghz (single core +3400 processor).

well, then they went into making 90nm processors (my x2 +3800 processor used this technology) and then they started making them with 65nm technology (my e6300 core 2 duo and my Q6600 use that technology). now intel makes dual cores and quad cores with 45nm technology, which produces quite a bit less heat and therefore can be clocked higher.. but its not easy to mass produce processors at smaller and smaller wire sizes.. they need to use a laser to produce them and it costs more for them to buy the machine that will produce them that way (probably millions of dollars).

soon enough (since their 65nm and 45nm processors obviously sold well) they will start producing the codename nehalem cores which are rumored to use 36nm technology and run 4 cores with 4 virtual cores (like hyperthreading). they will be able to handle 8 software threads with only a single processor. they will likely also be clocked above 3ghz at stock speeds, but who knows maybe it will perform more work per clock compared to core 2. its also referred to as "Core i7"

oh, and as a side note.. dual cores use the same amount of power as single cores.. and they therefore produce the same amount of heat... that's why intel doesn't make single cores anymore. they're generally non-existant except for in the extremely low-end market, i.e. celeron and sempron processors, and that's only to make a cheaper alternative for people who don't want dual core or don't need it.


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## jdbennet

i wish brian would stop saying that, hes wrong

on a side note ibm have an experimental pentaherts cpu  - its cooled by liquid nitrogen through nanohtubes in the cpus wafer itself. and it costs like a million bucks.


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## mep916

jdbennet said:


> on a side note ibm have an experimental pentaherts cpu  - its cooled by liquid nitrogen through nanohtubes in the cpus wafer itself. and it costs like a million bucks.



Wow.


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## just a noob

i remember when i was looking for the p4 world record, the site had the fastest cpu ever(at the time in 2004) made by ibm, it was stock at 350ghz, and they used liquid helium to get it to 500ghz lol


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## jdbennet

lol

more hz isnt nececerially better, FSB and Cache afftect it to


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## sandlotje89

@Fade2Green I'm incredibly impressed with your summarization.  You've helped clarify stuff that I haven't quite understood before.  Thank you so much for your post.

So what is the "wire" in reference to the processor?  I understand that the process of the processor is the width of the smallest wire, but I don't understand what the wire actually is.  If I understand correctly, the temperature of the wire is lower with lower processes because the amount of resistance is smaller.  If that is correct, then what exactly is creating the heat?  Is it each cycle of the processor (i.e. each wave of binary information)?


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## sandlotje89

Also, how does the processors wattage come into play?  In a simple comparison b/w the Q9650 and the QX9650 shows that the only difference is 35W of power, which must be pretty significant for the price to be doubled.  But to me they could say that the processor can consume 200W, and my jaw wouldn't drop -- just because I don't understand the significance.


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## bubblescivic

sandlotje89 said:


> So why are we not at PHz (Petahertz) yet? -- or even close to it?  Have proc companies and researchers lost interest in the speed and gone to researching and producing more cores?
> 
> I'm sure that procs at the PHz level would change a lot of things about computing.



1) removing heat from the cores that would run that hot.

2) there's not a need for that speed of cpu yet.

3) technology... different architectures have different capability per clock cycle. for instance, an amd x2 clocked at 3.0ghz is slower than a core 2 duo clocked at 3.0ghz. modify the architecture to be more efficient and faster and you have no need to remove heat from a superclocked cpu.


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