Yeah, performance with grids in back is abysmal. Like horrific. Even just clicking on a menubar item has 1 second of lag nearly. I don't recall it happening before. If it's a bug, please fix. Affinity Designer works blazingly fast with grids on or not. Really, Adobe. Come on. At least catch up.

Thanks for all the feedback and thank you Anki for the tip!

I've found that simply deselecting the "Grids in Back" preference seems to work.

I can confirm - for me at least - that unchecking 'Grids In Back' under Guides & Grid in Preferences works and stops the lag.
So worth trying if you haven't already.

Follow-up from my earlier post: I tried to set up a whole new document and copy over the icons. Which worked fine, as the pre-set grid was much bigger. As soon as I set the grid to 1px X 1px, the same problem occurs.

I then proceeded to try all sorts of different pre-sets, and the 1 px grid is the problem (as I have seen mentioned before in this thread)

What works for us now as a workaround (we need a pixel grid and the 'show pixel grid above 600% zoom' doesn't seem to do anything), is (after many, many trials) to set the grid to 2 px with 2 subsections, and uncheck 'Grid in back'

This has cost me a whole day of work (including many crashes and hours on the helpline), but I hope it helps other members in the community. Attaching screenshots in English and German.

I (and my team) have had this same problem for months now. We are working with a large icon file (each 24x24 pixels, optimised for as few anchor points as possible, pixel perfect, set on a pixel grid). Most of the icons are monochrome. The file was only 3.4 MB. Originally, we had over 600 art boards, and over 55 K anchor points.

I had tried all the recommended tricks, like switching from CPU to GPU view, etc. (but that made the zoom laggy). Today I spent more than 2 hours in the adobe help line, and gave various support staff access to my computer, where they tried a lot of things, deleted presets, and increased scratch disk memory. The problem persisted. I was then told the file was too complex, and there is nothing more they can do. And that I needed to reduce the number of anchor points, but they couldn't tell me to what number.

I proceeded to simplify the file, achieving a file size of 1.9 MB (!), 480 artboards and 49 K anchor points.

Sadly, the problem persists, and Illustrator immediately crashes when I try to show the grid in line mode.

I have a 2018 macbook pro, 2.8 Ghz 6-Core Intel Core i9, 32 GB 2400 MHz DDR4, Radeon Pro 560X 4 GB
Intel UHD Graphics 630 1536 MB, which I was told is plenty powerful for any Adobe app.

I would really appreciate if Adobe could fix this soon, as I cannot believe a 1.9 MB file can be the cause of such a massive problem. Thank you!

The default for the grid in the preferences is 72pt, but the more detailed the settings, the slower it runs, and it seems to hang at 2pt.

Same here on Windows 11 (and latest win 10 pro too), Illustrator 26 (latest release)
This is extremely blocking for work and frustrating for system as it makes the whole PC lag.

This is still an issue in Illustrator 26.0.2. If “Grids in Back” is on in Preferences, and grids are turned on from the View menu, the entire app is unresponsive for many seconds at a time. Illustrator becomes completely unusable, even with an empty document. For me, it doesn’t make a difference if I’m using the dot or line grid line style.

The issue is reproducible on two different Macs (one Intel, one Apple Silicon), and has been present across Big Sur and Monterey for me.

Bought new fancy mac pro yesterday with Monterey OS, installed new Adobe Illustrator from scratch, the same lag with grids still there :(

Issue happens when "Grids in Back" is turned on.

Update - issues is back after a few days. The only way around it for now is to switch to 'view using CPU' in the view menu. Now v26 has been released - what new bugs are in store I wonder?

I contacted Adobe Support via the chat box about this - they needed to remotely access my computer, check various things including fonts , re-set preferences and maybe a few other things - sorry I can't be specific. It took a while but they got it working again and now outline and grid view behave as they should with no lag. So it's worth contacting them to get it resolved.

Same for me too - Illustrator 25.4.1 - Mac Mini late 2012 running Catalina. If show grid is turned on and then you switch to outline view, Illustrator will become seriously unresponsive, taking many seconds to respond to any mouse click, moving objects, zooming etc, sometime it almost freezes entirely. When turning off the grid or switching back to preview the problem goes away. This has never been an issue in earlier versions of Illustrator.

Try changing grid style to dots — it helps until this bug will be fixed.

Same here, illustrator 25.4.1
If i hide the grid everything is fine, but i do need the grid.

Config:
MacOs Big Sur 11.6
iMac (Retina 5K, 27-inch, 2019)
3,7 GHz Intel Core i5 6 cœurs
40 Go 2667 MHz DDR4
Radeon Pro 580X 8 Go

hopfully they resolve this fast cause it's a pain in the a...
thanks !

Same. Why so little votes? Is this such a rare bug, or does nobody uses grids in Illustrator v25?
Big Sur v11.6, mbp 2018, 16gb RAM, Radeon Pro 560X 4 GB

The same thing here. My macbook overheats and slowdown so much, is really stressful to work like that.

Same here - Catalina and illustrator 25.4.1 on macpro 2109

Showing grid makes illustrator useless slow, when hiding, it works fine.

I should have mentioned that if I hide the grid I can successfully view in outline mode.

When trying to view outline mode (command-y) with an illustrator document that has a grid, it locks up illustrator and I get the beach ball balloon and "Illustrator not responding" so I have to force quit.

Illustrator 25.3.1

MacBook Pro 16-inch, 2019
2.4 GHz 8-Core Intel Core i9
64 GB 2667 Mhz DDR4
AMD Radeon Pro 5500m 8GB
Intel UHD Graphics 630 1536 MB

Having the exact same issues here!