Try hiding your timeline panel. Does that help?
There have been a few threads around here with people running El Capitan having issues with playback speed with AE CC 2015. Sometimes just messing with what panels are visible or where the mouse is can help.
How many monitors do you have? Sometimes turning a monitor off or moving all your panels to one monitor can help.
Alternatively, forget about the new architecture that has been partly done in CC 2015 . Wait until it works a bit better and continue to use CC 2014. If you don't have CC 2014, you can get it via the Creative Cloud app: How to Find and Install Previous Version of Adobe Apps in CC 2015 CC 2014 and CC 2015 can live happily installed on the same machine (heck, I have CS5, CS6, CC, CC 2014, and CC 2015 all installed at home with no issues). Plus, AE CC 2014 can even open projects created in AE CC 2015 without issue.
I'm using El Capitan with multiple monitors also. So maybe this is causing this terrible lag with comp viewer too?
This is a know issue? For sure it's not the OS fault because CC 2014 is working flawlessly.
What is happening with Adobe and Apple, now it seems they are releasing beta software as it were the final version? This is a way to call the big community as free beta testers?
Same config (latest iMac same specs), and same problem!!!
I have the same problem. Most recent version of El Capitan and After Effects. Hiding timeline panel as some have suggested doesn't help. Right-clicking in comp window doesn;t help (another suggestion from someone).
Mac Pro (mid 2010)
2 x 2.4 GHz Quad Core Intel Xenon
ATI Radeon HD 5770 1024MB
What works for me is putting the "composition" window in full screen.
You can do it using two methods.
First put your mouse over the window you want, in this case the composition window and then press the key I show you in the image inserted in this message (I took a photo because my keyboard is a French one so keys might not be the same).
The other way is to click "Full Screen" at the bottom of the "preview panel".
When the composition window is in full screen I can preview my animation at the wanted Frame rate...
By the way I find this version of After Effects not even on the level of a "Beta", there are so many bugs that in my opinion they shouldn't have released it.
Now I'm in the middle of a project, but as soon as I'm done, I'm going back to CC2014 which is a bit weird because it will be in 2016...
Thanks Merlin! That seems to work! I guess After Effects has trouble rendering all of the UI elements while previewing. Soloing the comp window as you suggest lightens the load enough for real time playback.
I posted on another thread:
The Adobe forums have been a useful source of information. Here are some other helpful links and info I came across:
HOW TO FIND AND INSTALL OLD VERSION OF ADOBE APPS:
ALL ABOUT PREVIEWS IN AFTER EFFECTS 13.x
FEATURES NOT AVAILABLE IN AFTER EFFECTS
http://blogs.adobe.com/aftereffects/2015/06/features-not-available-in-after-effects-cc-201 5-13-5.html (an older post, but some of these issues linger)
...Additionally if (like me) you are having issues keeping the Creative Cloud app running (i.e.: spinning blue gear or blank white box), here's some info about that:
1 Close the Creative Cloud application if it's running.
2 Navigate to the OOBE folder.
3 Windows: [System drive]:\Users\[username]\AppData\Local\Adobe\OOBE
4 Mac OS: /User/<username>/Library/Application Support/Adobe/OOBE folder
5 Rename the opm.db file to opm_old.db
6 Restart computer / Launch Creative Cloud
If you need to install Adobe apps manually, go here: http://prodesigntools.com/adobe-cc-2015-updates-links-mac.html
Happy I could help you JBXX.
I can only hope that Adobe starts to address these problems.
Because "real time preview" and "rendering time" are by far the most important features, and now both of them are broken.... It's really silly.