i5 or i7 for photo editing

That's what I would do Mike. The i5 is plenty powerful for light photo editing.

The i5 should be fine for photo editing with LR and PS with the files sizes you are dealing with.

Get the SSD and add the optional 16 GBs of RAM. Both LR and PS need CPU, plenty of RAM AND plenty of data storage space.

I use an older 3.06 Ghz core 2 duo CPU iMac with 16 GBs of RAM and with only a 256 MB GPU.

I am contemplating installing a 1 TB SSD in mine.

I create much larger PS files than you work with and my much older iMac seems to handle those higher PS file sizes well enough, now.

I think the i5 should work out plenty fine for your needs.

Good Luck!

I LOVE BOTH Affinity Photo AND Designer!!!!

Once Serif releases a few more major updates I may try totally swapping over to Affinity Photo.

RIght now, I am really torn between Pixelmator or Affinity Photo as my chosen Photoshop replacement as I am only a part-time freelance designer now (major, MAJOR heart issues at only 52 years of age) still using Adobe CS3 and do not like Adobe's AND AutoDesk's rent-a-software subscriptions and newer versions of Adobe CS (CS4, CS5, and pre-subscription CS6) are fetching prices, now, that are completely out of my financial realm and means to justifiably afford.

FWIW, Photoshop and Lightroom heavily leverage the GPU and not the CPU.

I currently use Photoshop CS6 on a late 2013 27" 3.2GHz i5 iMac and it

performs very well. So the newer i5 iMac should be even better.

I am also looking to Photoshop alternatives and have been playing with the

Affinity Photo trial and am pretty impressed. Starting to look now because

I know eventually my CS6 will end up being non-functional at some point

and I will not tie myself to the Adobe "ball and chain" software rental.

Something I forgot to mention as far as Photoshop substitutes.

There in an application called GraphicsConverter by Lemkesoft that has a very good

image browser, lots of adjustments and filters, and is capable of using Photoshop Filters, now.

It also can read a myriad of file formats and save to an equally impressive number of formats

(this was the apps original function when it came out many, many moons ago). I have at least

verified that my Neat Image noise reduction plugin works perfectly with it.

It is inexpensive and worth checking out.

While the i5 processor has plenty of power for light photo editing the 24-36 megapixel files you mention are very large. That will require plenty of processing power. I'd recommend the i7 processor along with plenty of RAM.

Processing photos uses the processor while games and high end video processing impact both the processor and the graphics display. For those planning to use the iMac for more than occasional video processing I would upgrade both the processor and the graphics card.

For the 24-36 megapixel photo processing the processor upgrade is the way to go IMHO. Also add as much RAM as you can. When I purchased my 5K iMac I ordered the i7 processor and the stock 8 GB RAM. I then bought a 16 GB RAM upgrade from Other World Computing. After installing the additional RAM my iMac has 24 GB RAM. I often run PhotoShop, InDesign, MS Office and Safari simultaneously and my iMac handles that very well.

mby852 wrote:

.....I don't know if you seen the new one by Macphun called aurora hdr. ....

FWIW, I was testing a demo of their Intensify Pro and had numerous crashes,

one was just when I was accessing a menu. Their latest batch of apps may

not be ready for prime time or just not ready for El Capitan (even though they say it is).

Ralph's comments aside.

GPU power is good, but is not pivotal for working with 2D images.

GPU power is great for video processing (although video is still working with 2D images), but is mainly good for animation and 3D modeling work.

I process 16 and 20 Megapixels images from bridge style cameras (a Nikon and Sony digital cameras).

I, actually, do not do ANY RAW file image processing of images and just work with large size jpeg files most of these style cameras generate.

The actual file sizes aren't THAT large and in most instances, today's Macs can handle large MB high resolution file sizes very well.

If you want to create posters from the initial large jpeg files digital cameras initially generate, you'll need to do some image interpolation as the initial size files won't have very good pixel resolution at their initial size.

I AM convinced, though,that Adobe keeps adding more software bloat to their applications products that alawys hinder image processing performance.

I use both Photoshop and Painter as creative painting and drawing tools and my Photoshop Master files routinely are in the sizes of 500 MB+ and some projects reach close to 1 GB in size.

My iMac and my CS3 version of Photoshop seems to handle these types of files pretty well on an iMac that is much older than what is available today and only uses an i3 Core Duo CPU, 256 MBs of VRAM and 16 GB of RAM.

I find, also, it is always best to run Photoshop by itself with no other CPU taxing applications or processes running innthe background, too!

If finances and cost aren't an issue for you, then do what will.

Both CPU models are quad core CPUs.

The only difference between the i5 and i7 CPUs is that the i7 CPU has hyperthreading technology ( running data through more data channel streams).

If you do not plan on doing lots and LOTS of video work or animation and/or CGI/3D modeling work, I think the i7 isn't worth the extra costs if your work is going to be more or less in 2D.

The i7 is overkill for what you are really going to use that new iMac for.

But, like I stated at the top of my reply to you, it's your money. Do what you want with it.

If you want still save yourself some cash, get a 27 inch screen iMac with only the base amount of RAM and purchase and install yourself cheaper, thrird party RAM, instead.

Apple charges a lot more for RAM than online third party Mac RAM sellers.

Correct, compatible and reliable Mac RAM can ONLY be purchased from online RAM sources Crucial memory (http://www.crucial.com) or OWC. (http://www.macsales.com).

DO NOT PURCHASE RAM FROM LOCAL COMPUTER OR ELECTRONICS STORES!

Macs are VERY picky about RAM specs and RAM from local sources will NOT work in a Mac.

RAM is relatively easy for new and novice Mac users to install.

http://eshop.macsales.com/installvideos/imac-27-inch-5k-late-2015/

Good Luck!