What's the difference between the i3 and the i5?

[the8thark]

What's the difference between the i3 and the i5?
Apart from the clock speeds what's the real difference between the 2 cpus? Specifically I want to get the high end 21.5 inch imac. The 27 is just too big I think. Anyways for roughly $250 Australian I can upgrade the i3 dual core to an i5 dual core. And I just am asking is this $250 well spent? Or is it just not worth the money?

 

[schweb]

Here's a good article:
Core i3 vs. Core i5: Differences Between Intel's i3 and i5 Processors

 

[the8thark]

Thanks Schweb. What I got from that article was:

The i3 does support hyper threading but not turbo boost. The low end i5 can turbo boost by 266 mhz. Big whoop. The 13 and i5 6xx series can have integrated graphics while the i5 750 can't. Which really makes no difference cause all the imacs have a dedicated gpu.

But the conclusion of the article is:

In any case, what this really means is that the Core i3 processor is the one to buy if you're on a budget. It only loses turbo boost, which in the low-end Core i5 processors is not an impressive feature. The Core i5 processors are faster, however, so if you're not constrained by budget they are also a good choice.

So in short what I get from the article is get the i5 cause of the higher clock speed. And do we know which series of i5's and i3's Apple is using now?

So if it's just clock speed. Then it's $261 for me for 400mhz more. As the article says all the other differences between the 2 add up to naught for most people.

The article recommends to get the i5. But just for a few more mhz is it worth it? My gut is telling me no. But the article and someone else I asked said yes it's worth it. So now I'm really confused on the subject.

[edit] This is what Apple's page says about the the i5 if you click learn more on the configure page.

All iMac models include processors from the blazing-fast Intel Core “i” series, featuring an all-new processor architecture that helps boost performance over the previous generation. Both the 3.2GHz Intel Core i3 and 3.6GHz Core i5 dual-core processors offer these advanced features:

4MB of L3 cache, which increases performance by keeping data and instructions in a fast-access cache that is available to all processor cores.
An integrated memory controller, which allows faster access to data stored in memory by significantly increasing memory bandwidth and reducing memory latency.
Hyper-Threading technology, which allows two threads to run simultaneously on each processor core, providing four virtual cores for increased performance.
Available on the Core i5: Turbo Boost, a dynamic performance technology that automatically speeds up the core in use when the other core isn’t needed.
Which processor speed is right for you? The more time you spend using processor-intensive applications — such as video processing, image editing, and 3D rendering — the more you’ll benefit from a higher-speed processor.

Funny that. The article said i3's do have hyper threading but Apple says they don't. Who to believe?

 

[bobtomay]

Aside from the obvious clock speed, you're looking at Turbo Boost with the i5. Have to realize that turbo boost only comes into play with apps that cannot make use of multiple cores. This is almost a moot point as we continue into the 64 bit realm as most of the apps that could really benefit in some time saving (ex. encoding), already make use of multiple cores, so you'll not get turbo boost with any of them.


While the i5-680 shows about 20% better benchmark scores than the i3-550, the few examples I've seen in real world work indicates you might see 6%, maybe 10% max benefit. We're talking about a max 1 minute savings in time on a 10 minute encode and probably more like 30-40 seconds on 10 minutes.

At a premium of 15% of the price of the computer, that $200-$250 (depending on where you are) would probably be better invested in other peripherals or software you want. Resale value of the i5, my guess would be an extra $50 to $100 max.

It's not a bad upgrade, but not something I'd recommend in this particular case unless you have the extra money and are one that enjoys knowing you have the best you could have gotten in your setup. Doubt very seriously that you'll notice any difference in daily use.

edit: The two chips I've noted in 2nd paragraph are the ones being used by Apple in the 21.5" iMacs. The last line you quoted from Apple is the real key related to video/image editing whether the i5 may be worth it to you.

edit 2: Apple is saying the i3 has hyperthreading. Have to put that period in there before the sentence starting with "Available on the i5:..."

 

[the8thark]

Thanks for the reply.

I don't have any other software I need to be honest. Maybe ilife 11 but that's it really. And I see your point. Nice to have but not really needed. Thanks for that. I understand.

But I have one last question.

The article said i3's do have hyper threading but Apple says they don't. Who to believe? Cause to me the hyper threading would almost be worth the $261 is the i3 does not have it. But does the i3 have hyper threading? I don't think so but the article says it does. I think you'd know if the Apple shipped i3's have it or not.

 

[bobtomay]

Catch my edit 2 above.

 

[s2odin]

The i3's have hyper threading but no turbo boost.
The i5 duals have hyper threading and turbo boost
the i5 quads have turbo boost but no hyper threading

 

[iggibar]

What's the difference between the i3 and the i5?
Apart from the clock speeds what's the real difference between the 2 cpus? Specifically I want to get the high end 21.5 inch imac. The 27 is just too big I think. Anyways for roughly $250 Australian I can upgrade the i3 dual core to an i5 dual core. And I just am asking is this $250 well spent? Or is it just not worth the money?

If I were you, I would pick up the i3, and use the rest of the money to buy a nice ssd. Too many reviews show inconsistent results...which is obvious when people don't really know what's a better choice. Obviously, the highest end i5 will be good, but you have to realize that those speeds aren't available to you all the time. The second the system detects higher temps, turboboost automatically gets "throttled down" or stopped. They have i3 iMacs at the Apple store, those "little" i3 still pack a pretty good punch! 3.06ghz is still fast!