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skywest153

macrumors member
Original poster
Jun 21, 2010
81
37
I'm currently evaluating options for the iMac and am curious as to what people would suggest here. I plane to do video editing as well as programming for a flight simulator game that I help produce.

I have a corp discount on Apple that puts the i5 27'' with 2GB GPU ram at about the same cost as a refurb i7 27'' with 1GB GPU ram.

What would you opt for, both in terms of longevity and the budget at hand?

Thanks!
 

apw100

macrumors regular
Jan 24, 2010
134
1
Jacksonville, FL
The i7, no doubt. The GPU w/ 2GB of VRAM will do NOTHING for your video editing, even with apps that utilize OpenCL (FCP-X, Motion, etc). It probably won't even have an effect on your flight sim experience either.
 

maus

macrumors regular
Apr 17, 2010
223
0
Sorry to resurrect an old thread, but this is exactly the question I am debating now, except with the 2013 27" iMac.

I believe there is a $10 difference between these two configs in the certified refurb section of the store.

I am using the iMac mainly for design work, so Photoshop, Illustrator, inDesign, etc. No real video editing and zero gaming.

Would anyone be able to comment on these two options for my usage needs?

To be honest, I've already pulled the trigger on the i5/2GB GPU option with a 1TB fusion drive, but am considering exchanging it for an i7/1GB build if it makes more sense.

Thanks in advance!
 

Renzatic

Suspended

Notechy

macrumors member
Apr 11, 2015
67
11
Surrey
this should give you a basic idea of the differences between an i7 and i5 in Photoshop

Of course there are situations where having those extra cores will come in handy. Like if you do a ton of batch processing, heavy multitasking, things that really hammer the CPU, you'll want an i7. Though for everything else, you won't notice any real difference between the two.

I have turned to this list but do not know which are the relevant retina iMac processors. Can you help please?
 

loekf

macrumors 6502a
Mar 23, 2015
824
568
Nijmegen, The Netherlands
I have turned to this list but do not know which are the relevant retina iMac processors. Can you help please?

AFAIK:

Late 2014 Retina 5k model:
i5 4690K or i7 4790K

Late 2013 model:
i5 4570K, i5 4670K or i7 4771K

Early 2015 Retina 5k model (speculation)
i5 4570K or i54670 @ 3.3 GHz ? Or special Intel part ? Guess a new type number and likely they are binning the parts (take some CPUs not able to reach 3.5 GHz, put a new type number on them and sell them for less to make more money out of normally rejected parts)

See

http://en.wikipedia.org/wiki/IMac_(Intel-based)

IMHO, the 5k model uses so called Haswell "refresh" parts. This was a small redesign of the Haswell CPU with higher clocks, redesigned package to better handle thermal load. However, the Intel part numbering scheme is a complete mess... it's impossible to see the CPU core architecture generations in the part number.
 
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loekf

macrumors 6502a
Mar 23, 2015
824
568
Nijmegen, The Netherlands
Of course i7 is updated and better. But I have tried i5 with 2GB.

Problem is that an i7 will only "shine" if you have multi-threaded apps. The main differences between i7 and i5 are:

- 6 MB cache vs. 8 MB
- Hyperthreading

I guess the more threads, the more a bigger cache is relevant. Hyperthreading will also ensure the cores are used to the max in case you use lots of threads. An i5 with its 4 cores, will have to do more context switching => more cache thrashing, less efficiency.

For normal usage, you shouldn't notice the difference. I can't imagine basic usage of OS X and some apps will stress an i5.
 

maus

macrumors regular
Apr 17, 2010
223
0
this should give you a basic idea of the differences between an i7 and i5 in Photoshop

Of course there are situations where having those extra cores will come in handy. Like if you do a ton of batch processing, heavy multitasking, things that really hammer the CPU, you'll want an i7. Though for everything else, you won't notice any real difference between the two.
Thanks! Yeah, I did some research before my purchase and was aware of Photoshop's minimal use of hyperthreading, which was why I went with the i5/2GB GPU config.

I guess I wanted to ask here to see if there were any differing opinions from what I've read in various places. I mainly want to know if the trade off of the i7 for a 2GB instead if 1GB GPU makes sense. Also, I believe my i5 is the 3.4 rather than 3.2ghz model if that makes a difference. I'm not that familiar with graphic cards, so I'm probably only biased towards the GPU because of what I do, haha.
 

loekf

macrumors 6502a
Mar 23, 2015
824
568
Nijmegen, The Netherlands
Thanks! Yeah, I did some research before my purchase and was aware of Photoshop's minimal use of hyperthreading, which was why I went with the i5/2GB GPU config.

I guess I wanted to ask here to see if there were any differing opinions from what I've read in various places. I mainly want to know if the trade off of the i7 for a 2GB instead if 1GB GPU makes sense. Also, I believe my i5 is the 3.4 rather than 3.2ghz model if that makes a difference. I'm not that familiar with graphic cards, so I'm probably only biased towards the GPU because of what I do, haha.

I've read stories about 1 GB GPUs running out of video memory resources if you use programs taking lots of resources from that video memory. That's why I originally went for a 2GB 27". However, I bought a baseline 5k (= 4x more pixels) with a 2GB card instead. Guess you're safe...
 

Renzatic

Suspended
I have turned to this list but do not know which are the relevant retina iMac processors. Can you help please?

The new iMac refresh is using the i5-4590 as the base, the i5-4690 for the mid, and...er, some i7, I can't find out which. They're all Haswell based, and will all roughly have the same single core performance.

Really, the only thing you need to concern yourself with is if it's an i5 or an i7. Or rather, 4 cores vs 8 cores. For any multithreaded program that only takes advantage of 2 to 4 cores, you won't see much difference between an i5 or an i7. The i7 does have some bonuses that come with its higher clock speed and slightly bigger cache, but it won't make an earth shattering difference.

Now if you're using a program that can take advantage of all the cores it can get, or you're doing heavy multitasking, which is not just having a bunch of programs open, but are actively using them (IE rendering 3D in one program, while spicing together audio clip on another at the exact same time), this is where the i7 starts outpacing the i5. You have double the cores (or rather, the same amount of cores that can handle two threads at once, rather than just one), which means you can juggle more more gracefully, do one really big task that much quicker, or both.

Movie editing or 3D rendering will benefit more from an i7. An i5 isn't exactly sucky here, but it won't finish tasks quite as fast. For image editing and web design, an i5 will work just as well as an i7, since you'll rarely ever need more than 4 cores.
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
The new iMac refresh is using the i5-4590 as the base, the i5-4690 for the mid, and...er, some i7, I can't find out which. They're all Haswell based, and will all roughly have the same single core performance.

The i7 in the retina iMac is the Devil's Canyon i7-4790K, but probably with the unlocked multiplier disabled in the OS X side (or even in Windows, if it's locked via the UEFI).

Not too different from the i7-4770K vs the i7-4771 (used in the 27" non-retina). My best guess is that the i7-4771 is basically an i7-4770K without the unlocked multiplier for Apple.
 

rosario1990

Suspended
Feb 1, 2015
250
13
Dhaka, Bangladesh
Problem is that an i7 will only "shine" if you have multi-threaded apps. The main differences between i7 and i5 are:

- 6 MB cache vs. 8 MB
- Hyperthreading

I guess the more threads, the more a bigger cache is relevant. Hyperthreading will also ensure the cores are used to the max in case you use lots of threads. An i5 with its 4 cores, will have to do more context switching => more cache thrashing, less efficiency.

For normal usage, you shouldn't notice the difference. I can't imagine basic usage of OS X and some apps will stress an i5.

Yeah, that's right may be.
 
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