Acrobat becomes very slow when I open large PDF files (200+ pages).

You are not imagining it, and it is usually not really the file size, it is how much vector and text detail sits on each page. Acrobat re-renders the whole page on every scroll and zoom, so a 200-page set piles that up fast, even with plenty of RAM.

Worth trying in Acrobat first: Preferences, Page Display, turn off Smooth line art and Enhance thin lines, and toggle Use 2D graphics acceleration (it helps on some GPUs and hurts on others, so test both ways). On really heavy files it only goes so far though.

Disclosure, I make a PDF tool built for exactly this kind of heavy file, so I am biased, but the underlying point holds either way: tools that render based on what is on screen rather than the whole page stay smooth where Acrobat bogs down. If it helps, here is a reproducible side-by-side of a dozen editors on one heavy drawing, with the test file included so you can try your own: https://ncored.com/pdf-benchmark-cad-drawings.html

(Disclosure: Ncored maker.)

The extract-and-optimize routine shared above is worth trying first. If the file itself is bloated with scanned images or embedded fonts, that alone can bring Acrobat back to usable.

If the slow files are drawing sets exported from CAD software (AutoCAD, Revit, and ArchiCAD exports are the usual culprits), the problem is usually not file size but the amount of vector detail on every page, and optimizing only gets you part of the way. Rendering preference tweaks help some people, but the complaint pattern has been around for years.

For that specific case I ended up building a desktop PDF app, Ncored, made for heavy drawing sets: it opens fast and stays smooth on scroll, zoom, and pan even on a 50-200 MB+ project set. Windows and Mac. 14 days free. No signup, no email, nothing to enter. If your 200-page files are mostly text rather than drawings, stick with the optimizer route above, it is the better fix for that.

Hi ​@James_Anderson5352 ,

Adding my 10 cents here. 

The shared file opened with no issues on my end. Two things, there are new Windows updates and Acrobat updates.  If this is happening with both software reflecting their most current latest versions, disregard.

Otherwise, see if performing the updates on both improves the issue. 

I also work with very big files (from 100 MB up to 1 GB), with several hundreds to some thousands of pages. So, the lagginess is even worse for me. Each small edition, like moving or duplicating a page, takes 2-3 minutes, and saving the file takes 10-20 minutes.

I also have more than enough CPU and RAM for Acrobat to run. (The usage of resources by the program remains under 10% for the CPU and 50% for the RAM, most of the time.) And I work always with local files (stored in an SSD, not an HDD), never files in the “cloud”.

I asked Perplexity for the possible causes and solutions, and tried almost everything the AI found in the Internet. (Except for compacting/optimizing the file, what in my workflow is the last thing I do, after all editions are made, to avoid loosing important information.) I timed the operations and the net result was negligible.

I even created a RAM disk and moved to it the PDF files being processed and the /AppData/Local/Temp folder where Acrobat saves some temporary files, to no avail. Clearly, the bottleneck is not the speed of the media where the files are stored.

My conclusion is that the problem is in Acrobat itself, particularly the way it builds and deals with the data structures retained in memory while processing the PDF files. Without any open file, completely idle, the program occupies circa 500 MB in memory. By just opening a same sized PDF file, it increases the memory usage to 6 GB. That means that the data structures it creates to merely “understand” the PDF file are 11 times bigger than the file itself! (5,5 GB divided by 500 MB.) And as the work progress, the memory gobbled up by the program increases continuously to double, to triple that size! (And the lagginess increases proportionally.)

So, unless Adobe uses some AI to rewrite the source code of Acrobat, in order to optimize the way the program treats large files, there’s nothing we users can do.

The strategy I found to ameliorate the problem is:

• To fractionate the file and work with each part separately. But if I need to work with two or more parts simultaneously (for example, moving pages from one part to another), it’s the same as if I worked with one non-fractionated file.
• To save the changes and close periodically the program (for example, at every hour), then reopen it and continue the work. This reinitiates the data structures that Acrobat creates for dealing with the file.

That slow-open-then-laggy-scroll pattern on 200+ page files is common once a PDF tool is handling a big document. The first load stalls, and then panning and zooming stay choppy no matter how fast the machine is.

A couple of things worth trying inside Acrobat first: turn off Protected Mode at startup (Preferences, Security Enhanced) and disable the cloud document features, since those add overhead on open. They buy a little, but on very large files they only go so far.

(Disclosure: I make Ncored, so weigh that accordingly.) I am a practising architect and built it after Acrobat kept sitting for 8 to 12 seconds on our drawing sets. It opens large files fast and stays smooth on scroll, zoom, pinch and pan, including heavy 50-200 MB+ project sets. Windows and Mac (Apple Silicon), no subscription, and 14 days free with no signup, nothing to enter, so you can test your worst file before deciding.

@James_Anderson5352  try this first... and maybe the Acrobat Preferences isn't the issue.... 

DO you have the 'New Acrobat' Interface on or off? If you go to View is it: 

• Enable new Acrobat (it's off)
• Disable new Acrobat (it's on)

If 'it's on' I would turn it off. It It will automatically restart Acrobat. It has been noted that many who work with large, complex, or heavily annotated documents—report that this new interface has a detrimental impact on performance and responsiveness. Test this if it works... if not...

In Acrobat Preferences (Command K for the MAC, or Control K for the PC), under Page Display, uncheck the following in Rendering: Use Page Cache; Smooth text, Smooth line art, Smooth images

as well under 3D & Multimedia change the Preferred Rendered to the Software — We are trying to speed up the rendering.

You could even re-save the same PDF under a different name, and Compress the PDF - Advanced Optimization to a lower resolution! 

*NOTE: Some people will suggest change and uncheck the security preferences, which can also bog the PDF down—but I normally don't because for me it's all about safety and security to my computer and documents