P: Performance problems iMac Retina 5k

It might be that it's a different problem, but as I mentioned- the guy at my apple retailer sad it accours with most 'creative tools'. I guess you did not try a blown up logic X project or a ablation live set with some plugs. Anyway - we would know if we are talking about the same thing if you would consider your logs. Any time I get a freeze the log is full of the following error message: WindowServer[...]: GPU Driver appears to be hung (over 5 continuous seconds of unreadiness)

Maciek Niemczyk, it's just that Lighroom's performance is the same as on my 2012 MacBook Pro with 16GB RAM, old graphics cars, 4x slower SSD, older processor. I bought a new supercharged computer thinking it was time to upgrade in order for Lightroom to have a better performance.

Here are more details from a previous post of mine. I need to mention that my 64GB RAM is NOT OEM, but someone suggested that I test performance with the original Apple RAM, which I did...16GB (that shipped with the iMAC). Same thing. And last, but not least, how come ALL other applications that I use perform well, excellently, and only Lightroom has sub-sub-par performance? And the forums and support pages are filled with complains of Lightroom performance?

Here are the details:
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Hello everyone.  

I need to share my experience with Lightroom CC 2015.4 on brand new and powerful iMac and see if other people experience similar performance issues. Is it my setup or is it indeed the application that needs refinements? Also I want to share a weird bug presented by Photoshop CC 2015.1.2 and see if anyone can reproduce this.

Until 2 weeks ago I was using a 

• MacBook Pro mid 2012, retina
• 16GB RAM
• 2,7 GHz Core i7 processor.
• 750GB SSD
• NVIDIA GeForce GT 650M 1024 MB
• OS X El Capitan 10.11.3
• Adobe Creative Cloud - applications always up to date
• Using mostly Lightroom and Photoshop (I'm a photographer, that's my job & passion)

Well, this is a pretty decent computer, but over the last couple of months or a year it has been running progressively slower and slower when running Lightroom. Photoshop was behaving more or less OK having in mind the specs and age of the MAC. But eventually Lightroom became so slow, I cant even describe the slowness. I as looking at the spinning wheel more time than working on an image. Lightroom was slow in all modules. Normally I also have Mail and Safari opened and some times Photoshop. Back in time, some 6 months ago, I first started closing one of those apps to slightly improve LR's performance. Then I had to start closing all applications and only leave LR running. My computer became a dedicated machine to Lightroom, only to try and have some work done at the end of the day. 

Strangely enough, there was always free RAM (I use Bjango's iStat Menus to constantly monitor RAM and CPU in the OS's menu bar)...some times as much as 25%-40% free RAM. But Lightroom was behaving as if there was none. 

So a few weeks ago I decided that my old pal the MacBook Pro has to be retired, although he was performing VERY WELL with all other applications...But I understand that Adobe applications are complex image editing power softwares and resource hungry. So I did a huge investment in the latest and greatest, fully loaded iMac...

Two weeks ago I received my iMac and I've been using it intensively ever since, doing my observations and taking notes. And after 2 weeks I had to reach out to the forums and cry out my frustrations. Because there are such...and as I see, I'm not alone...First the iMac's specs:

• iMac 5k, late 2015 model, 27", fully tuned and loaded with 
• 64GB RAM;
• 4,0 GHz Core i7;
• 1TB SSD (no fusion drive) by the way it's 4x faster in read & write times than my old MacBook Pro. Performance was measured with Blackmagic Disk Speed Test v. 2.2.2 and the iMac's SSD exceeds the scale with over 1200MB/s write and 1900MB/s read speeds;
• AMD Radeon R9 M395X 4096 MB;
• OS X El Capitan 10.11.3
• Adobe Creative Cloud - applications always up to date (currently LR CC is 2015.4, CR is 9.4, PS is 2015.1.2)

Well, overall performance is better, indeed. But it's far from what I expected. Don't get me wrong -- the iMac is performing AMAZINGLY well with all other applications. But with Lightroom I still see the spinning wheel a lot of times. For the folders with images that I'm currently working on I render full resolution 1:1 previews +  Smart Previews (so in fact I'm working on the internal iMac SSD). Rendering edits lags. The spot removal tool is so badly slow and lagging, that I prefer to export the file to Photoshop and clean it there. How is this possible?

Before I get asked let me answer: yes, I do use the graphics processor (the option is selected). I tried both options.

What does happen then, do you have application freezes or is there something else. What does your console log look like at this moment, and is your RAM original or did you upgrade with a different RAM?

It's not the RAM's problem and it's not the MAC's problem. On my 64GB of RAM ALL other applications work amazingly fast, snappy, just as expected even exceeding expectations...The computer is amazing, the performance is stunning...until I open Lightroom and start working in it. It's Adobe/Lightroom's problem. 

Problem solved. Cancelled my decision to buy an iMac 5K. Switching to Capture one. Goodbye Apple, goodbye Adobe.

That really is amazingly unacceptable. the iMac 5k costs a lot of money. It's been months and I'm still sort of not accepting the reality that the computer is almost completely useless for what I got it for. Crazy. 

I dont think it can be fixed, I ordered a new pair of crucial ram certified for this iMac and had the same problem. It seams not to run well with different ram then the one it was shipped with, and there is no way to buy the original ram. That's really an issue here.

I would if they say it clearly before one buys a iMac to have the ability to choose one with enough ram, even if the ram from Apple is more than twice expensive then the one on the market. But this way the only option is to sell it (with bad feeling) and buy a new one with more ram. So a ram upgrade cost about 1K. That's the opposite of customer satisfaction.

So are we still just waiting on this to get fixed? 

i can't believe this hasn't been resolved yet. it's driving my photographers crazy. 

Thanks for the tip, @Chris Cox... I will try with the original Apple 8GB of RAM and see if there is any difference