i5 or i7

[T'hain Esh Kelch]

This is a common misconception.

With the i7, you are looking at ... marginal improvements in intensive tasks (gaming included) and small improvements in highly parallel intensive tasks (such as video encoding).

I guess it wasn't a misconception after all then (Even though I never said anything about the i7). A small difference still adds up to a significant one in the long run.

 

[leman]

I guess it wasn't a misconception after all then (Even though I never said anything about the i7).

You said 'best machine you can get',so I was assuming you meant a maxed out setup The thing is, that after some point you run into diminishing returns: a slight increase in performance will cost you much more money. And this slight increase won't help you with some future demanding applications. After all, whether a future game will run at 20 fps max or (20 +5%)=21 fps, doesn't make any difference at all.

A small difference still adds up to a significant one in the long run.

This I absolutely agree with. If you make money from computing time, e.g. by doing compiting-intensive photo processing for customers, a slightly faster CPU means that you can do additional one or two photos a day, thus increasing your income. Provided that you are swamped with orders

 

[gnasher729]

Second, I suppose I should have given more info as opposed to having people guess based on my grammar and sentence structure haha. Tanax got it most right. I was already sold on the Fusion Drive from other threads and intend on getting it, and since it was only available on high end 21.5", that was my choice. And I was going to add the i7 because it was only an extra $200. Now that Fusion is available on low end, i7 becomes an extra $400.

In case anyone is wondering why the price changed from $200 to $400...

2.7 GHz i5 -> 2.9 GHz i5 = $200
2.9 GHz i5 -> 3.1 GHz i7 = $200

The $250 for Fusion Drive is the best value for money for almost everyone. The difference between i5 and i7 is more than the difference between 2.7 and 2.9 GHz, so the one I would _not_ buy is the 2.9 GHz i5. If all your CPUs are at 100% for long time then the i7 is worth it, otherwise it's not.

 

[Confuzzzed]

...Provided that you are swamped with orders

And that you work to full capacity, with not a moment's pause to get on your favourite Apple websites and don't white space at all

 

[Nunyabinez]

Don't know if the OP is still around but here is my experience. I ran the Cinenbench benchmark on my 3.4Ghz i7 iMac. It computes the performance of a single core and the the multiple cores together. My multi-core ratio is 4.78. I am making an assumption here, but if there were no multithreading, the multicore ratio should be 4 if 4 cores are running instead of 1. So, that means that I am getting an additional 20% out of my i7 than I would with an i5.

However, that difference only comes into play when all cores are close to being 100% utilized. Watching my menu meters, I am usually barely tapping the capacity of this machine. However, when I use something like handbrake, I ping out the meters. If I were doing hours of handbrake converting, the i7 would make a difference (a 20% difference). But, usually I set a conversion to take place while I'm eating dinner and it's done in real time or shorter.

So, I have to agree that this decision really hinges on how you use your computer. For the vast majority it won't come into play that often and the difference seems negligible. However, it would bother me not having an i7 because I like being fast, even if I'm not using it much.

 

[Mac32]

Well, the i7 makes a big difference in Unigine demo. Don't know if the same difference would show up in a proper game setting though. I've seen several people claiming that hyperthreading gives you noticable performance benefits in BF3 during level loading and with online multiplayer maps with many opponents.
I ended up ordering the i7 myself, although I was very unsure since i7 is a hotter CPU than i5. I couldn't help myself thinking "hey since I'm paying a fortune for the SSD, 680MX and 16gb ram, I might as well go for the faster CPU". Don't forget you also get 2mb more onboard cache, and 0.2-0.3 ghz more speed. Not a lot though...

However, I've seen benchmarks with i3 CPUs with and without hyperthreading (dual core CPU), and the difference in framerates was quite big (can't remember the specifics). So maybe there's potential for hyperthreading and quad core CPUs in future games? On the other hand, for the kind of large resolutions needed on the 27' iMac, the GPU is far more important than the CPU. I've seend several people state that hyperthreading makes multitasking a bit more snappy, lets say you're tabbing out of a game to check out something on the Internet. It's difficult to ascertain the veracity of online forum comments though...

 

[T'hain Esh Kelch]

Not necessarially. The mobile i5 chips do have hyperthreading, but the desktop i5 chips do not. The i5 in the iMac is a desktop chip, and does not have hyperthreading.

Good catch. I actually didn't expect Intel to remove HT from the 3rd generation i5, hence why I wrote it had it as the second generation does.. So strange, as the i3 does have HT..

But, I would never buy in on HT for gaming. Even if some games use it, the majority don't. And an even better argument is that unless you plan to go for a Mac Pro, you'll *never* be limited by CPU power, but by the graphical capabilities of the GPU! Barefeats has tons of graphs to show this.