Quad Core vs Dual Core

[Art M.]

Do any of you know whether quad core is an advantage over dual core when it comes to editing photographs in Lightroom and Photoshop?

I'm debating MacBook pro 13" (dual) vs 15" (quad) and really, I'd rather have the smaller one. The issue is whether the quad core would make Photoshop and Lightroom run noticeably faster when editing photographs.

My impression is that Photoshop and Lightroom use only one core, so what matters more is the speed of that one core, in which case the 13" at 3.5mhz is actually faster.  But I do not know for sure and have not tested.

I get into very detailed editing on headshots. Lightroom, including the latest Classic, will bog down tremendously sometimes when there are lots of edits.  (otherwise it's not bad!)

All of my software is most current version, always. Currently using a 2015 MBPr 13" maxed out I7 16gig memory. Considering the latest (2017) MBPr models.

SO, do any of you know whether quad core is an advantage over dual core when it comes to editing photographs in Lightroom and Photoshop?

Thanks!

Art

ps: I have read that use of the dedicated GPU on a 15" would actually slow down these programs when editing photographs. That it's best to turn off the dedicated GPU. Have any of you confirmed that via testing?

[dj_paige]

The important piece of information is not the inch size of the monitors, but the pixel size of the monitors (height and width). Please let us know.

In general, Lightroom runs fine with dual or quad core CPUs, probably faster with the quad core, but you know this depends on a bunch other things, such as the size in megapixels of the original photos (do not tell me megabytes) and the speed of the CPUs, and what kinds of editing you are doing (lots of brushing? lots of spot healing?). And probably other things as well.

[Todd Shaner]

https://forums.adobe.com/people/Art+M.  wrote

I'm debating MacBook pro 13" (dual) vs 15" (quad) and really, I'd rather have the smaller one. The issue is whether the quad core would make Photoshop and Lightroom run noticeably faster when editing photographs.

Currently using a 2015 MBPr 13" maxed out I7 16gig memory. Considering the latest (2017) MBPr models.

Given the above information you won't see much of a difference with the 2017 MBP 13" 3.5GHz dual-core. The 2017 MBP 15" i7 with 2.8GHz quad-core configured with 16GB memory should provide a noticeable improvement (1.5x to 2.0x). Or wait for the 2018 models and compare their specs.

PassMark - CPU Performance Comparison

[Art M.]

Good point, I forgot to ask whether the 2017 13" itself would be faster than the 2015 13" ....

[Todd Shaner]

Sorry, I've added those details in my original reply above to make it clearer.

When making comparisons you can use the PassMark CPU Mark score as a "relative" LR performance calculation. You can find the MBP processor model using the speed (GHz) and generation (7th, 8th) posted on Apple's website here: Intel® Product Specifications

You then need to to factor in any difference in the display resolution in Megapixels For example the 2017 MBP 13" 2560x1600 = 4.1 Mp and 2017 MBP 15" 2880x1800 = 5.2 Mp. So you would need ~ 1.25x more CPU/GPU performance for parity between these two models in LR performance. Whatever model you get make sure it has 16GB or more memory.

[D Fosse]

https://forums.adobe.com/people/Art+M.  wrote

My impression is that Photoshop and Lightroom use only one core

That's a common misconception, but not correct. Here's what it looks like with 4 cores/8 virtual cores. This is just going crazy with the sliders in Develop:

Photoshop will give a similar picture. Beyond six cores however, you get diminishing return on investment.