Alright, everybody experiencing issues: Let’s all step up and send Fabio the information he’s requesting above. Let’s help with action to get this issue resolved.
A gentle reminder for those experiencing GUI issues on Mac: Please contact Fabio as requested at the top, with specifics.
I disagree here,
I use Protools and can have 150 audio tracks with over 600 plugins in total on these running smooth like butter in real time.
Mixing there is a breeze. I just really prefer the cubase toolset for editing and programming midi based music.
but the performance is not even close.
Please, let’s not continue this side discussion on this thread. I will end it here: This is factually not a DAW problem at this time, as I (combined with others I personally know plus others on this forum) experience the problem on Cubase but not in Pro Tools, Reaper, Logic, and Studio One.
Mac OS was indeed causing similar problems with Pro Tools, but AVID fixed it (I use PT 12 on my system to work on projects from before I switched to Cubase a few months ago, and it is smooth as butter GUI-wise).
Again: The problem does not exist currently on Pro Tools, Reaper, Logic, or Studio One. I’m only writing that to show that it is not a DAW problem for these other DAWs. 
No, sorry, I don’t agree. If we want to get to the bottom of this it’s not possible to disregard known issues because you are not experiencing them. This was even discussed on the Apple developer forum as an issue affecting El Capitan and (to a minor extent) Yosemite - I’m not aware of any radical change with Sierra either.
The outcome is system specific and can affect different programs in a different way - Logic is no exception, in the KVR thread there is a Cubase user experiencing issues with Logic and not with Cubase (also check the JUCE forum link, even plug-in developers have different experiences with different hosts).
Every report is useful, even if it does not prove your point 
Kidding aside, I’m very interested to understand where this issues comes from and why it seems to affect real-time apps in particular and gather as much info as possible.
As for the issue specific to Cubase, sending the info to me as written above will help more than any discussion.
Edit: In_Stereo, I received your latest e-mail, thank you and thanks to those who sent in their report, will get back to you ASAP. Sorry for the ‘Christmas delay’!
I hear you…I didn’t realize it was affecting users in other DAWs besides Pro Tools (before version 12, though?). Thanks again Fabio, and I hope people continue to send you their system reports, as this is this only way we will help get to the bottom of this! I’m wondering if you could make your request for information a sticky so that people will see how important it is?
Yup. Made this a temporary sticky, so that it’s more visible and more affected users can chime in.
Hi I have issues with all my tracks I’ve written in Cubase 8 and earlier. Cubase 9 makes screen redraw extremely slow, unusably so and also seems to degenerate quickly to the point that there are spinning disc delays when doing any different operation e.g. you try to move a part, big delay, then try to move it again and its quicker. Select a different track, spinning disk … wait selected…
Noticed something interesting - some plugins are updating OK while the other and the main screen are frozen during these times e.g. I had Kramer master tape updating without a glitch while Curve EQ and L2 were stuck for the period of time - all these 3 were on the same channel. Could this be core distribution??
Cubase 8 is fine and does not do this. I have more or less given up on C9, waiting for another update but would be happy to try things / troubleshoot. Have sent email to info with more details and info report.
cheers
Alan
6 core, El Cap, lots of tears
Sorry to hear there are some issues on this.
Here all has been fine to be honest. As we all list music making kit rather than graphics cards - could that be something worth investigating?
Using an Intel Iris Pro 1536 MB here on a 2013 iMac.
Lowering the resolution solves all my slowdown and lag problems, but you have to make sure it’s really a low resolution and not just “scaled”. On the resolution window, you have to hold the option/alt key when pressing the “Scaled” button, then check the “Show low resolution modes” box and then try out some of those low resolutions. On my 5k iMac it gets ridiculously slow if I used my native resolution. I hope this workaround works for anyone else who has slowdown and lag problems on a mac.
I’m glad it works, and thanks for posting. I’ll try it just for the hell of it, but this is not an option for me at all as I have gigantic film scoring sessions and need as much screen real estate as possible in order to avoid literally constant clicking/scrolling. A lower resolution would make Cubase unusable for me, and I would guess for most others.
I’m also having some issues with slow Cubase GUI on OSX 10.11.6 El Capitan.
I’m using a NVidia 950GTX with the NVidia web drivers. I’m using 3 monitors:
Two of them running on DVI Ports and HD resolution (1920x1080) and the 3rd one running at 1680x1050 to an HDMI port.
This machine is a hackintoshed PC that runs everything normal. I also use here at my studio: Pro Tools 12.6 and Studio One 3 and they seem to perform ok.
I have Windows 10 running on another HD on the same machine and cubase 9 runs pretty fast there.
I also have a Macbook Pro with El Capitan and cubase 9, Cubase 8,5 and Cubase AI 8 and all of them have the same lag problems as my main studio machine.
My Cubase is 9.01 and 8.5. Both have this lag on GUI.
I did a test project with 30 empty channels and dragged the same stereo wave file to all tracks.
The lag is very big. Every time I click on G or H for zoom, it takes a while to respond. And while the lag is happening, the meters on the console freezes. So, if I hold G or H for a while to do a full zoom in (or out) the meters just freeze until it goes full in (or out).
I tested reducing from 30 to 12 visible channels on screen and the lag reduced and If I scroll down to just show only one channel of those 12, it seems to perform way faster, with minimal lag (still a small lag) but the same lag as If i had only one channel on my project.
I noticed a bigger lag when I switched my setup from 2 displays at 1680x1050 + the 3rd one at 1400x900 and went to 2 displays at 1920x1080 and the 3rd one at 16801050.
To do some tests, I just resized cubase main window and it seems to improve A LOT the performance when the window is very small. That explains why I had less lag on lower resolutions.
I did a small youtube video showing the lag. Lag on Cubase 9 and Mac El Capitan 10.11.6 - YouTube
I also sent an email to Fabio with those info. 
Hope it gets fixed soon
Thanks for the suggestion.
Running ATI Radeon HD 5770 with 2 x thunderbolt connected monitors here.
Turned resolution down to 1024x768 (they were the days) and loaded one of my C8 projects into Cubase 9 and its still unusably slow. Spinning ball when selecting a part etc etc.
Doesn’t seem as bad on new tracks however.
cheers
Alan
I have the same CPU and GPU as you. What are your monitor specs? (Thunderbolt seems well beyond the capabilities of that GPU card)
I wonder if as others have said this is a graphic card related issue.
I have the new MacBook pro with Intel HD Graphics 530 1536 MB which I think is different to a lot of the ones stated here.
Would be happy to test out but I only have cubase 8 and will not pay to upgrade unless I know it works - if and when there is a trial cubase 9 I will report back.
Hi
My monitors are both Dell U2412M. It was either mini DP or thunderbolt, but I think the mid 2012 Mac pros were all thunderbolt?
Anyone with the same as me working OK in C9?
It seems much better with projects created in C9, all those I’ve tried saved in C8 seem to be very err stunted. 
regards
Alan
No - Thunderbolt is on the “new” Mac Pro only (2013).
Major issues aside, do you find the meters responsive (no latency) on new projects in C9?
Also, do any meters or eq animations “stutter” when hovering your cursor over buttons and such. (see video example in my second post here: Mac GUI animations laggy - Cubase - Steinberg Forums)
Thanks.
thanks jpgtr
Yes I’m seeing the same on my machine. C9, new project, moving mouse around over any object and the meters get laggy. Not as noticeable as in your video but it does degenerate the more you add.
Something fundamentally needs fixing IMHO
cheers
Alan
Hello,
sorry for the silence, the official entry for this is [CAN-6382].
This is a new, separate entry to the one previously created for Cubase 8.5.
Hopefully someone has been able to repro this in-house or perhaps engineering can advise about which tools can be used to diagnose the slow-down on Mac. Although reported, I’m not moving this to the ‘Collected’ forum so that you can keep on posting further details.
Thank you all.
Thanks Fabio! Much appreciated. I’ve worked more with Logic X lately because of the GUI issues on Mac. Logic visually runs extremely smoothly. The play head in Cubase staggers like a drunken sailor trying to keep up…and that’s on a project with just one simple audio file and no plugins at all. ( my video is in the bugs forum)