What's the difference between an Intel Core i3, i5 and i7?
- — 11 May, 2011 11:07
Intel Core i3, Core i5, and Core i7 CPUs have been around for over a year now, but some buyers still get stumped whenever they attempt to build their own systems and are forced to choose among the three. With the more recent Sandy Bridge architecture now on store shelves, we expect the latest wave of buyers to ask the same kind of questions.
Core i3, Core i5, Core i7 — the difference in a nutshell
If you want a plain and simple answer, then generally speaking, Core i7s are better than Core i5s, which are in turn better than Core i3s. Nope, Core i7 does not have seven cores nor does Core i3 have three cores. The numbers are simply indicative of their relative processing powers.
Image credit: Intel.
Their relative levels of processing power are also signified by their Intel Processor Star Ratings, which are based on a collection of criteria involving their number of cores, clockspeed (in GHz), size of cache, as well as some new Intel technologies like Turbo Boost and Hyper-Threading.
Core i3s are rated with three stars, i5s have four stars, and i7s have five. If you’re wondering why the ratings start with three, well they actually don’t. The entry-level Intel CPUs — Celeron and Pentium — get one and two stars respectively.
Note: Core processors can be grouped in terms of their target devices, i.e., those for laptops and those for desktops. Each has its own specific characteristics/specs. To avoid confusion, we’ll focus on the desktop variants. Note also that we’ll be focusing on the 2nd Generation (Sandy Bridge) Core CPUs.
Number of cores
The more cores there are, the more tasks (known as threads) can be served at the same time. The lowest number of cores can be found in Core i3 CPUs, i.e., which have only two cores. Currently, all Core i3s are dual-core processors.
Currently all Core i5 processors, except for the i5-661, are quad cores in Australia. The Core i5-661 is only a dual-core processor with a clockspeed of 3.33 GHz. Remember that all Core i3s are also dual cores. Furthermore, the i3-560 is also 3.33GHz, yet a lot cheaper. Sounds like it might be a better buy than the i5. What gives?
At this point, I’d like to grab the opportunity to illustrate how a number of factors affect the overall processing power of a CPU and determine whether it should be considered an i3, an i5, or an i7.
Even if the i5-661 normally runs at the same clockspeed as Core i3-560, and even if they all have the same number of cores, the i5-661 benefits from a technology known as Turbo Boost.
Comments
Rafa
Thu 12/05/2011 - 00:55
Great explanation, just the simplelist and best explanation i could find :D
Bill
Thu 12/05/2011 - 10:11
Exactly the overview I was Googling for. Clear, concise and understandable. No one else has put this in plain terms. Thank you PC World, good article.
David
Sat 14/05/2011 - 00:29
Really good explanation. I understood the difference well now. Thanks ;)
Cameron
Sun 22/05/2011 - 18:00
great explanation - until I found this outline I was starting to think that I would never find a useful overview.
Murrh
Thu 26/05/2011 - 18:57
Concise, if all cores active, can turbo boost increase clocks still? amd turbo core will only initiate when less than 3 cores active on their hex chips 1055t 1090t.
if maxing out the processor on all cores, for extended periods, would there be any difference between the i5 dual and an i3 similarly clocked?
colleen
Mon 13/06/2011 - 09:09
just purchased a dell i5 notebook - 17.3 inch screen for $850.00 from qvc is this a good deal?
Richard
Wed 15/06/2011 - 12:20
just wow. now i fully understand what to buy now, tnx for this great explanation
Joshua
Sun 03/07/2011 - 07:48
which computer would be best for gaming but is also cheap because my price range is 250 to 350 dollars
Steve Holanov
Mon 18/07/2011 - 11:11
Apparently no one proof reads these articles. Why do you say that someone interested in performance is better of buying an i5 than an i3 when you cleary state that the i3 supports hyperthreading and the i-5 doesn't? There is nothing that clearly indicated the benefit of an i-5.
Hari
Mon 18/07/2011 - 12:22
Hey, This is good post for me. Now I can have idea of i3,i5 & i7 concepts. Thanks
Synchro
Thu 28/07/2011 - 06:25
"However, the Internet browser you use to access Netbank or your email client is not"
Sorry, that's just plain wrong. Any app that does more than one thing at once (e.g. a web browser that loads multiple images simultaneously; a mail program that gets mail from more than one account at once) is extremely unlikely to NOT be multithreaded.
I'm on OS X (and any other modern OS will be similar) on an 8-core machine and right now I can see that my IDE is using 66 threads, Aperture is using 45, Firefox 26, Safari 13 (and another 9 content threads), iTunes 17, Skype 23, Mail 16 and many, many others for a total of over 800 threads in 175 processes. As you can see, any one of those everyday apps will happily spread their work across all the cores I have available. What matters is how much the CPUs are actually being utilised for this workload - on my system, I run out of disk bandwidth long before my CPUs get choked up, so I'd be better served by an SSD upgrade. I suspect this is common - I'd expect an i3-based system with an SSD to run rings around an i5 with a regular HD for everyday tasks.
Tommy
Fri 05/08/2011 - 15:42
Nice article, but you can this info off intel's website or even the CPU box in some cases. Technology really is making people less intelligent. A lot of the comments here reflect that, but not being able to remove the battery cover off a phone is priceless. Seriously PC World, please look at the comments being posted on your site.
Antisynchro
Tue 30/08/2011 - 05:30
In reference to Synchro's comment: I'd expect an i3-based system with an SSD to run rings around an i5 with a regular HD for everyday tasks.
Please get your head out of your anus, you are likely to suffocate.
The reason you have so many threads running, is that you have quite a few different apps running. Web browsers are typically single thread apps. Sure, they load quite a few items very quickly. But, it is linear data transfer. Not raw processing power.
Paulette
Thu 08/09/2011 - 13:21
The explaination was great. Help me decide which computer to buy that will last a while. Thanks
Neha
Thu 08/09/2011 - 20:47
Great article. Really well explained in clear, simple terms. Definitely gave a good insight into what laptop to decide on. Thankyou!
Speckk
Fri 16/09/2011 - 09:13
@Steve Holanov Glass Houses and stones.
4 full native cores in an i5 are more powerful than the i3's 2 hyperthreaded cores (which can only run simple instructions in parallel some of the time).
That and the i5 has turboboost and 6mb cache compared to 3mb cache.
rohit yadav
Thu 22/09/2011 - 01:59
i just wanna buy new laptop can any onehelp me which one is best for me , my oly purpose is for surfing , little bit gaming ...advice me a affordable laptop it sholud be of hp ....
NIck the head
Wed 28/09/2011 - 07:26
As a headteacher and a prospective purchaser of 10 new laptops for staff you have just saved us about £750, so many thanks!
rjtkumar81
Sun 02/10/2011 - 21:16
According to me i7 is the best. I have i7 which is of 2.8Ghz and is quadcore and I compared it to my friend's i5 which was of 3.33 Ghz and was dual core. In my windows experience index I had 7.4 for the processor where as my friend had 7.0 anly for his processor.
gavinT
Wed 05/10/2011 - 06:55
I don't get it. Im looking to buy a 13 inch mac with i7 and it says it's a dual core. Only the 15 inch is a quad core.
Justus
Fri 14/10/2011 - 21:56
Thanx for the explanatn u gave...so dual core processor n core-i3 processor's the same..jst name differ...rite?
SpEcTaToR
Fri 04/11/2011 - 16:24
Thank you for the simple explanation.Now I'm thoroughly clear why an i3 is not an i5 and why an i5 is not an i7.
Happy computing!
Barb
Sat 05/11/2011 - 05:52
I was in a large electronic store yesterday shopping for a new computer. My old one has 3MB memory and when I buy I like to upgrade. I have been looking at computers with 6 to 8 MB. The salesman said that if I purchased one with i7 that it would run hotter and burn out faster. Is this true or was he just blowing smoke?
ProSynchro
Tue 08/11/2011 - 18:19
In reference to AntiSynchro:
"Please get your head out of your anus, you are likely to suffocate." How pleasant - starting your comment with an (undeserved) insult.
"The reason you have so many threads running, is that you have quite a few different apps running. Web browsers are typically single thread apps. Sure, they load quite a few items very quickly. But, it is linear data transfer. Not raw processing power."
Very few non-trivial applications operate in a single thread - I haven't worked on one professionally in my entire career in software engineering. To suggest that IE is processing all that Javascript, downloading, rendering text & images, collecting user input and protecting you from malware ALL IN ONE THREAD is fanciful. How is it that I can interact with a webpage whilst elements of it are still loading? Because separate threads are handling the user input & rendered output. I don't usually bother to respond to inane threads like this so, I guess congrats are in order for you - I have been successfully trolled by your post into responding...
maria
Sat 12/11/2011 - 10:50
hi! im looking to buy a very good and high speed laptop 16.4 inches for a simple use at the present and maybe in the future i will use it for something more advance.. can you help me find something?? and also could u tell me what do u think about the sony vaio VPCF22M1E/B ...
pandiyan
Tue 15/11/2011 - 15:56
hwllo sir, i need some information,first one is:what is improve of i5then differend between i3 and i5,plz reply me
GANESH
Mon 28/11/2011 - 14:10
good explanation.i just thought i3 have 3 cores,i5 have 5 cores and i7 have 7 cores wrongly.thanks for the explanation and difference in intel cores
pandiyan
Tue 29/11/2011 - 00:21
Thanks for your explanation.This is very useful to learn the new comers.
Annie
Wed 07/12/2011 - 23:56
That was really helpful as I am considering buying a new PC. Thanks!
sayali tayade
Sun 11/12/2011 - 20:30
i need a laptop with core i5,..which will be best in that case with lowest price but best quality..
Starr
Thu 15/12/2011 - 13:16
Thank you so much for the break down. I now understand about i3, i5, and i7 Intel Cores.
Brandon
Sun 18/12/2011 - 10:14
Short, concise and to the point. Thanks for the easy to understand explanation. You've now helped me rule out the i3 process for my laptop computer selection. Now I just need to decide between the i5 and i7 mobile chips...and then each chipset thereafter under i5 and i7...
lulu..
Wed 21/12/2011 - 17:47
ahh haa! now i understand all the hoopla is about. my pc usage is well below i3s. but still good to know for future reference. THANK YOU.
Tony
Wed 28/12/2011 - 22:02
Just wanted to say thanks for the advice on differences in i3 to i7... For a lay person with a little knowledge on computers this has helped greatly.
Suresh
Mon 02/01/2012 - 04:10
Very nice explaination. It helped me a lot to decide what I should buy.
Ghayth
Thu 05/01/2012 - 05:56
WOW, This article is AMAZING, I'm a computer engineer and I find it very useful, THANK YOU!!
wakilnikzad
Thu 05/01/2012 - 17:00
Okay guys,
I don't know the meaning of core i3, i5, or i7
what does the i mean here?
I heard that i3 means (4 cores) i5 means (6 cores) and i7 means (8 cores) is it true?
please if anyone knows help me thank you in advance
Balaji
Sun 08/01/2012 - 16:32
Okay. Whether is it good or well suited to buy these processors in laptop or PCs in performance wise?
Please anyone of you illustrate this..
IFremen
Fri 13/01/2012 - 13:28
Wow, what a thorough, clear, and easy to understand explanation! Thank you so much.
Gurulucious
Tue 17/01/2012 - 15:06
nicely explaned i dont quite understand the part where u said that all i3 are duo core i have a toshiba core i3 with a quad core please help am lost! happy computing
bg in Georgia
Wed 18/01/2012 - 02:53
Perfect - thanks for the clear and useful explanation! I don't usually stop to say thanks, but this was great.
David
Sun 22/01/2012 - 21:44
For every day needs like email , web , a movie any one of them is ok . When buying the extremly fast computer , processors unless you have a need for this you are often paying extra for things you wont use fuly most of the time . I am using a core duo E4300 still. It dos every think plays HD movies ,web , emails ,every day things .
MichaelCornish
Fri 27/01/2012 - 13:53
Tons of help i loved it! Just one thing what is the difference?
Grant Carlisle
Tue 07/02/2012 - 17:18
Actually. I'm not a 100% sure about the rest but i do have a Vaio VPCCW21fX with an I3 That does infact have 4 Cores. I have also seen a couple I5 with dual cores. can you explain this?
wingxero
Sun 19/02/2012 - 19:25
Hi im planning to buy a laptop can i ask something which is better??
Acer 4755 - i7 and 8GB ram
Or
Sony Vaio S Series i5 8GB ram?
Of course sonny is a little expensive than acer but what do you think might be the one i need? Will use it for games and ordinary downloading on the go
Many thanks
TheGoldenDread
Tue 21/02/2012 - 22:11
THANK YOU PC WORLD!!! THAT WAS NICE AND SIMPLE!!!! Geesh everyone else i looked up was giving like super detailed like i understood any of it..smh.
Thanks Again PC world for making that simple.
Rich
Sun 26/02/2012 - 01:55
Thanks for the insightful article. Simple and to-the-point - finally!
Ned
Mon 27/02/2012 - 15:28
I agree with Rich: this has been an extremely lucid, focused and user friendly explanation, of great relevance to consumers of the new computers. As a technical illiterate who does not keep up with what is often incomprehensible (and who has in the past been incorrectly advised because I tend to underestimate what I actually end up doing on my computer!), I struggle with so much: but even I understood this and can apply it to my next purchase. Thank you so much!!
suhail
Sat 03/03/2012 - 17:29
in i3 or i5 , i stands for what? as p stands for pentium i stands for?
Samba Julius
Sat 10/03/2012 - 23:20
Insight view; so helpful, but could you please shed light on the turbo side of it. thanks
no
Mon 12/03/2012 - 23:28
The comments on this page are some of the stupidest things I have ever read.
Tua TARARO
Thu 15/03/2012 - 14:29
I have the i5661, stock speed 3.33ghz, but now running at an overclocked speed of 4.60ghz. Air cooling with a mux120 push/pull fan setup.Very stable with core temps around 40ish deg celcius, love it.
Early Grayce
Thu 15/03/2012 - 18:43
I still use a i5 750 and a GT460 for gaming and can play Skyrim and Mass Effect 3 with no problems even though I only have 4GB of Ram
Fred Botz
Sat 24/03/2012 - 16:28
Sheesh...I have a headache from reading some of these idiotic questions: "...I would like to know what is the best chip for my computer? I want to play killer games but only spend 150.00? How much ram does the I7 have? What is the best computer to buy? How fast will my computer go with one of these? Will this make my disks run faster?"
Some people should just stay away from computers altogether...
snake
Sun 01/04/2012 - 02:45
thanks clearned alot of my doubts and filled alot of grey areas! great article :)
Karambir
Mon 02/04/2012 - 15:43
A good basic computer knowledge for Tyros.
Thank you for making it simple.
Chase
Tue 10/04/2012 - 12:55
Thanks for the explanation. Well, I'm off to order an alienware with an i7 processor... cheers :D
A part of a brain
Sun 15/04/2012 - 13:54
Thanks, you explained something so complicated in such simple terms. It makes it a lot easier to understand
Jasmine
Sat 28/04/2012 - 01:00
Very good article. Concise, informative, and easy to be understood. Thank you!
Jake
Sat 28/04/2012 - 01:20
My laptop's i5 (560M) has both Turbo Boost 2.0 AND Hyper-Threading (I can see 4 graphs on Task Manager). But still with only 3MB cache.
Vijay Chimtekar
Wed 02/05/2012 - 13:34
I wanted to buy core i3,is this good for enjoying internet????
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Fri 11/05/2012 - 10:24
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anon
Tue 15/05/2012 - 02:58
WRONG!
i3 = dual core
i5 = dual core + dual threads + turbo
i7 = quad core + dual threads + turbo
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