Beginner Please explain Computer Processors & what makes a 'fast' computer?

Uncle Fester

Uncle Fester

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I posted a question on this thread:

https://www.talkphotography.co.uk/threads/is-this-laptop-ok-for-processing.673045/

I wondered if a particular laptop I was considering was up to photo processing and general internet surfing. Whilst it would seem that it would be up to the job; it was pointed out to me that the I7 processor was dual core and not quad core. As I would like any new computer to last awhile; I’m now thinking that perhaps I should get as good a specced machine as I can afford.

I realise that I don’t really understand processors at all and thought I’d ask some basic questions about them and what makes a ‘fast’ machine.

Firstly is a I5 processor always better/faster than a I3 processor and is a I7 processor always better/faster than a I5 processor?

In other words could a quad core I5 be faster/better than dual core I7?

Looking at processors on Ebuyer I looked at this one:

Intel Core i5-8600K 3.60GHz LGA1151 Processor £228.26

https://www.ebuyer.com/805378-intel-core-i5-8600k-processor-bx80684i58600k?mkwid=s_dc&pcrid=233884821978&pkw=intel%20core%20i5%208600k&pmt=p&gclid=CjwKCAiAlL_UBRBoEiwAXKgW54wkR-cd-sWasRzqko4JCfN49CZMghqyhuHet0NCn2-rfqNRK-039hoCkiIQAvD_BwE

I notice the specs say:

Performance

# of Cores 6

# of Threads 6

Processor Base Frequency 3.60 GHz


Then I noticed this one:


Intel Core I7-7700 3.60GHZ Socket 1151 8MB Retail Boxed Processor £267.70

https://www.ebuyer.com/766076-intel-core-i7-7700-3-60ghz-socket-1151-8mb-retail-boxed-processor-bx80677i77700
  • # of Cores- 4
  • # of Threads- 8
  • Processor Base Frequency- 3.60GHz
  • Cache- 8MB
The I7-7700 processor is quad core and has eight threads the I5-8600 has 6 cores and 6 threads.

I’m presuming the I7-7700 is the ‘better’ processor as it costs more; but I don’t understand why it has fewer cores than the I5-8600K.

I have no idea what ‘threads’ are.

Could someone please explain processor hierarchy and what to look for when wanting to choose one that is speedy?

Also; what else do I look for in a computer to ensure it performs well? I understand that the more RAM the better; but I should really have two sticks of memory so that I get dual channel memory - is that correct?

Is there anything else I should look for to maximise performance of any computer I buy?

Please keep any explanations simple and non-technical as I don’t really understand computers at all!

Thanks
 
To be fair it is a bit more muddy than that it depends how your software uses multi processors, also laptop processors are often M type which is lower power than full fat processors.

look at a benchmark site and see the numbers relating to certain processors.
 
Each processor core can handle one thread or two. Which depends on whether the processor has "hyperthreading." Look at the total number of threads rather than the total number of cores, but even that is not the full picture.

Amount of cache, processor generation (how well things like speculative execution works) etc all affect total performance, which is why benchmarks that simulate usage cases can potentially provide the best insight.

To be honest anything based on a modern i5 or i7 is going to be fine for the use you set out in the other thread (make sure you get 8GB RAM or more though)
 
There are a lot more variables than just processor speed, you might have a Ferrari but you are not going to get through the rush hour traffic any faster than the person in the Ford Focus. And there is always going to be a faster what-not for a higher price. And whatever you buy will only be good for 3 to 5 years, for example suppose you buy the best processor you can afford now hoping it will be good for 5 years but someone comes out with a blindingly fast new network technology in 2 years time. Often the only way to get that speed boost is to get a new motherboard and that means a new processor. Do you stick with the old network tech. or go for the upgrade?

What tends to happen is once there is sufficient uptake for a new, faster technology the software writers, content producers, camera manufacturers, etc. tend to assume everyone has the new tech and so make it almost impossible to stick with the old tech for too long. I know this doesn’t answer your question but it hopefully helps you make the right value decision about buying the most high-end (and high-price) components now, or buying mid-range now and accepting an earlier upgrade.
 
onomatopoeia said:
(make sure you get 8GB RAM or more though)
Click to expand...

:agree:
Yes, for photo PP I got an i7 with 16GB. A good friend and
colleague — who is on the video production side on life —
got the same machine but cranked it to the top RAM.
 
I find cpubenchmark.com good to generally compare CPU strength against each other.

It runs a bunch of tests on multiple samples of each CPU and gives an average overall score and other info.

Some will say benchmarks are not real world tests but it gives a very good idea what ones have strong computing power.

Desktop CPUs are much stronger than laptop ones.

A i7 3770K desktop CPU from 2012 still out scores a very good 2017 laptop CPU that was found only on very high end laptops last year, the Intel Core i7-8650U
 
Appreciate for the speedy replies.

I'll try to digest the above info - further questions may follow....

Thanks.
 
All modern Intel cores since about 2012 have roughly the same ipc (instructions per cycle) so think of a core as being a ‘core’

So clock speed and number of cores are a good differentiation.

Laptops cores run at lower power/lower speeds so are not directly comparable to a desktop processer.

For this reason a desktop i3 dual core can be faster than a laptop i7 dual core.

Up until recently Intel only banged out four core consumer chips but with the 8th series of cpus (coffee lake) they have added an extra two cores.

So an i5 now has six cores but no hyper threading so only 6 threads.

An i7 now has six cores and 12 threads.

An i5 with six cores is roughly equivalent to a four core i7 with hyoerthreading so eight threads.

To complicate things (and they were so simple..)

Because Intel have kept the consumer cpu market at four cores for years, almost all software is designed to run optimally on four or less cores. So having more than four cores in 2018 isn’t going to suddenly set Lightroom on fire. Indeed it won’t make any difference.

However going forward and for future proofing it would make sense to get the best cpu you can and that at the moment is coffee lake six core i5’s or i7’s.
 
Brazo said:
To complicate things (and they were so simple..)

Because Intel have kept the consumer cpu market at four cores for years, almost all software is designed to run optimally on four or less cores. So having more than four cores in 2018 isn’t going to suddenly set Lightroom on fire. Indeed it won’t make any difference.
Click to expand...

They also slowed down each core did they not so the performance boost is not as good as one would think at first glance.
 
GTG said:
They also slowed down each core did they not so the performance boost is not as good as one would think at first glance.
Click to expand...

Intel also segment their i7’s so you can have a top of the range ‘k’ model at 5ghz and the vanilla version at 3.8ghz and an energy saving version at 3ghz etc.

They also confuse things with turbo mode so the cores may be at 3.8ghz but spool up to 4.5ghz when needed. It may be however that only 1/2/3/4 cores turbo updependant on numerous factors, the main one marketing!
 
For image processing there is also how fast data is moved around inside the computer, so it is useful to have a solid state drive that delivers data at a higher rate and with much shorter seek times than a conventional spinning disc. Also using paired memory instead of a single stick allows information to be transferred through 2 channels instead of 1.
 
To answer the OP, it depends.

If the process is mathematically heavy, more, faster cores can help.
If the process is more dependent on moving data in and out of storage, faster RAM and SSDs can help.

For general purpose, I'd spec a decent mid range SSD and RAM, then see what budget was left for the processor.

PS threading. A core is a multistage pipeline. Traditionally you launched an instruction and it went through all stages, then you launched another. Multithreading is a process whereby you don't wait for the CPU to finish, you wait for the previous process stage to finish. It normally speeds things up, not always.
 
st599 said:
To answer the OP, it depends.

If the process is mathematically heavy, more, faster cores can help.
If the process is more dependent on moving data in and out of storage, faster RAM and SSDs can help.

For general purpose, I'd spec a decent mid range SSD and RAM, then see what budget was left for the processor.

PS threading. A core is a multistage pipeline. Traditionally you launched an instruction and it went through all stages, then you launched another. Multithreading is a process whereby you don't wait for the CPU to finish, you wait for the previous process stage to finish. It normally speeds things up, not always.
Click to expand...

Thanks for that - an explanation even I can understand!

I appreciate the clear and simple way you have described things; it makes it easier to grasp the basics which is something that isn't easy (at least for me) when looking at specs on paper.

I suppose in an ideal world, with a healthy budget, you would want a fast processor, the maximum amount of RAM and a SSD. Are there any other potential bottlenecks to performance?

Oh; and is 'hyperthreading' different from 'multithreading' ?

Cheers
 
Uncle Fester said:
I suppose in an ideal world, with a healthy budget, you would want a fast processor, the maximum amount of RAM and a SSD. Are there any other potential bottlenecks to performance?

Oh; and is 'hyperthreading' different from 'multithreading' ?
Click to expand...

Again it depends. If you rely on external harddisks, then the speed of the port. If you're doing very intensive graphics work, the speed of the graphics card. I doubt generic photo and video editing will require anything specialist.

I think Hyperthreading is Intel's marketing term for a type of multithreading. It's quite a difficult process - you can imagine that if instruction 2 depends on instruction 1's output, then you can't launch that immediately after 1 - so the Hyperthread controller has to look at what the code is doing and re-order the instructions but in a way that doesn't affect final results.
 
st599 said:
Again it depends. If you rely on external harddisks, then the speed of the port. If you're doing very intensive graphics work, the speed of the graphics card. I doubt generic photo and video editing will require anything specialist.

I think Hyperthreading is Intel's marketing term for a type of multithreading. It's quite a difficult process - you can imagine that if instruction 2 depends on instruction 1's output, then you can't launch that immediately after 1 - so the Hyperthread controller has to look at what the code is doing and re-order the instructions but in a way that doesn't affect final results.
Click to expand...

Thanks again; much appreciated. (y)
 
Uncle Fester said:
Thanks; much appreciated.
Click to expand...

No probs Danny. :)

Another useful gizmo on Intel's site is the 'compare' feature:
  • Find a processor (e.g. the i7-2600K in my earlier link), tick 'add to compare' (top right of page)
  • Type another processor name (e.g. i5-8600K) in 'search specifications' box top right of page - wait for 2nd page to load, then tick 'add to compare' again
  • Now click the blue 'compare' button
  • You should get both specs side-by-side, like this: https://ark.intel.com/compare/126685,52214
This makes it easy to see the differences between CPUs - far easier than scrabbling around countless other websites.
 
Uncle Fester said:
I posted a question on this thread:

I wondered if a particular laptop I was considering was up to photo processing and general internet surfing. Whilst it would seem that it would be up to the job; it was pointed out to me that the I7 processor was dual core and not quad core. As I would like any new computer to last awhile; I’m now thinking that perhaps I should get as good a specced machine as I can afford.

I realise that I don’t really understand processors at all and thought I’d ask some basic questions about them and what makes a ‘fast’ machine.

--SNIP--

Please keep any explanations simple and non-technical as I don’t really understand computers at all!

Thanks
Click to expand...

Here's an analogy to help you out...

Think humans...

Computer's processor is like a person's brain. Single processor doing work is like one person doing work. Dual core processor is like one person doing two tasks at the same time. Quad core is like one person doing four tasks at the same time. Not every one can do multi-tasking, so some people want to do one task at a time, but some others could be able to do multi-tasking, therefore dual core processor is like one person doing the cooking while at the same time doing a crossword puzzle.

In the computer world, it is more like a single core is a computer kind of "Hey! Let me do the downloading and installing first, I'll do the back up later, one at a time!" while dual core is like computer saying "Duh! I can download/install and back up at same time!" In the computer world, a quad core is like computer saying "Uh! I can do downloading/installing, back up, anti-virus, and do the maths with your spread sheet at the same time!"
 
Great explanation.

Even my woefully underspecced processor (brain) can make sense of that!

Many Thanks.
 
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