Lightroom CC and CPU usage

[PeterAit]

Why is LR (according to Task Manager) using 15% of my CPU when it's open but not being used? And is it normal for LR to use 2 GB of RAM?

[Simon Garrett]

Why is LR (according to Task Manager) using 15% of my CPU when it's open but not being used?

It could be doing background tasks such as building previews.  Does it eventually stop using cpu?

And is it normal for LR to use 2 GB of RAM?

Pretty normal in my experience.

[Paul2660]

My experience shows, you need to allow LR as much ram as possible.  There is no way to assign ram as you can in Photoshop CC, so besides running some memory mapping program, I don't know of a way to see exactly how much ram is being used.  Task Manager shows an estimate as you have pointed out, but I have never felt it's all that accurate a tool. 

LR seems to have no capabilities to work with Open CL and a GPU at least on the 3 windows and 1 MAC I have running LR CC, and on the Windows machines the GPU if selected will tend to slow LR down quickly. 

As much as I love the tool, the current progress that LR seems to have made, is totally negative.  Slower, more bugs, more lockups, but by far the single biggest issue I have is LR and the time it takes to load a preview at 100%, at times as long as 10 seconds or longer.  These are images with a lot of adjustments and history.  It really drags. 

During these slow phases, I have check task manager and a couple of tools I have to monitor memory temp/usage and LR will have close to 85% of the available ram (the ram which is not allocated to the OS and running the PC), so it's safe to assume on a 32GB ram machine, LR is paging the heck out of the system.  Paging is slow and not efficient at least in windows world as you are running on virtual ram on a hard drive, (SSD doesn't matter as it's still much much slower than a stick of RAM).  Using the system ram instead of the GPU is not a positive process.

For the record, I see the same terrible sluggish performance on a brand new 4.0 i7 with 32GB of ram as I do on my 2.5 year old 3.4GHz with 32GB of ram. Both are using nvidia 4GB v-ram cards. 

Other apps, Photoshop CC or Capture One on these same machines run circles around LR. 

For now, I have given up on LR and only use at time.  Just the fact that LR can't take advantage of a GPU is enough reason to look elsewhere, it's been a known issue for over 2 years now, documented hundreds of times on this forum and others, and still Adobe has not found a way or want to address it.  Instead they load new features like the HDR and Pano tools, both of which were broken at release and still are.  You can see 2 very well documented posts on this site where I have described the issues with these tools.   You can clearly see visually the effect of turning on the GPU with Photoshop CC, as zooming, or moving around a particular file slows dramatically with the GPU support turned off.

I would rather like to see less feature improvements and more fixes to the core of the LR code allowing it to run faster and with more consistency.

Paul C

[Peter McLennan]

Agreed, Paul.  The ongoing GPU issue is inexcusable, as are several other problems.  LR needs to focus more on performance and less on silly features like the book module.
Some problems are inexplicable.  For example, recently I've had several stitching failures in LR yet PSCC stitched the same images perfectly.

[Paul2660]

Agreed, Paul.  The ongoing GPU issue is inexcusable, as are several other problems.  LR needs to focus more on performance and less on silly features like the book module.
Some problems are inexplicable.  For example, recently I've had several stitching failures in LR yet PSCC stitched the same images perfectly.

Exactly,  you can take most failed pano stitched attempts in LR, export them to CC/pano and they work fine.  The pano tool works around 85% for me, and when it does very well (unless I am merging multiple HDR dng files, then it will always overexpose the highlights too much beyond the ability to pull them back).  But it can also throw up and not work on a series of files that it seemingly should, for no reason.  Which to me just points to possibly lack of full testing of the program feature. 

One other issues, (I know that is not the place sorry), the pano feature drops all local adjustments, which I find a bit strange.  WB, sharpening, profiles etc carry over, but if need to use an adjustment brush on a part of the file (say to work on sky), then you have to wait to do it after the pano merge. 

Paul C

[Simon Garrett]

My experience shows, you need to allow LR as much ram as possible.  There is no way to assign ram as you can in Photoshop CC, so besides running some memory mapping program, I don't know of a way to see exactly how much ram is being used.  Task Manager shows an estimate as you have pointed out, but I have never felt it's all that accurate a tool. 

I had no reason to doubt the memory usage figures given by Task Manager or Resource Manager, but if they're not accurate then I'd appreciate knowing.  Task Manager gives various figures including working set, peak working set, private memory, commit size and so on. 

From my observations, LR normally uses 2-4G most of the time, very occasionally more.  I have 32G and I've never seen LR use more than 5G.  It likes as much processor power as you have - but in single core speed.  It makes relatively little use of multi-threading except for background tasks (building previews and exporting).  That means single-core speed is the main metric, rather than number of cores.  Also it makes no use currently of the grpahics processor except in Develop Module, and it's not clear to me that it makes very extensive use even there. 

Photoshop on the other hand is a real memory hog.  With a 36M pixel image, create a few layers and memory use starts to sky-rocket.  I've certainly seen over 16G in use.  But I've rarely seen it max out on CPU. 

[Paul2660]

Simon,

I agree with your statement. 

Depending on the accuracy of Task Manager, on my main PC, LR holds between 2.8 to 3.7GB of ram, depending on the operation. 

However on the CPU side, anytime anything is done, Load a new image, zoom to 100%, move around an image at 100%, export an image, use or modify an adjustment brush, the CPU (in my case, 3.4Ghz, i7, not overclocked intel), the CPU jumps from around 4& to close to 100% then drops back to 75, to 5 after the stated operation is done.  It seems to show that the operation is threaded between all 8 thread pretty evenly.

Whereas Photoshop CC does just the opposite and holds much more RAM. 

I was just surprised to see LR CC not working any faster on a new i7 4.0Ghz, as it basically runs the same as on my older PC.  Screen shot below is caught as LR is loading an image up to 100%, which on this machine can take as long as 10 seconds.

Paul C

[PeterAit]

It could be doing background tasks such as building previews.  Does it eventually stop using cpu?

Pretty normal in my experience.

I was just out for most of the afternoon and when I came back LR was still using 15% of the CPU.

[aduke]

Sounds like it is stuck trying to do something and not being able to do it. Is there are disk usage while using 15% of the cpu?

Alan

[mcbroomf]

I just opened LR CC.  No tasks running.  It went to 15% CPU then started cycling.  It's now cycling (slowly) between 0 and ~11%.  This does correspond to it'd reported disk access, up to ~3MB/s (and slightly lagging).  Reported RAM use is 2.15GB
Win 10, i7 3,5GHz, 32GB Ram

[fdisilvestro]

I was just out for most of the afternoon and when I came back LR was still using 15% of the CPU.

Is it possible that you have Face Detection turned on?

[PeterAit]

Is it possible that you have Face Detection turned on?

No face detection. But this morning when I started LR it behaved as expected = 0% CPU use when not being used. Another mystery!

[dtrozzo]

Are you syncing with LR mobile? Is address look-up on? When I turn these features off cpu usage drops.

[happypuppy]

Try setting the cache to 10-15 gigs. It's independent to physical memory. I suspect it's processing

I have not worked for Adobe but I have a pretty deep background in development of imaging systems. A lot of stuff happens in the background. Indexing updating keyword lists etc



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