High Memory Usage and Performance Issues in Zotero 7 When Handling PDFs

jorathan

I've been suffering from the performance issues of Zetero 7 for several months since upgrading from version 6.

1. Opening any number of PDFs consumes at least 1GB of RAM. This memory usage increases dramatically with each additional PDF I open.
2. When I have multiple PDFs open, the loading times become very slow, and I'm experiencing frequent stuttering, which is impacting my workflow significantly.

I do believe many users like me don't have high-end computers with much RAM, and we need to run multiple applications alongside Zotero for our research. I also used another PDF reader handles well 10+ PDFs with only around 300MB of RAM. So I think optimization is possible.

Beyond memory, the performance issues are severely impacting my workflow. For a typical research project, I need to read many articles, and the constant stuttering and freezing in Zotero 7 are hindering my daily work. Many of my students and colleagues have stopped using Zotero 7 due to these issues, and while I prefer Zotero, the performance is becoming a serious problem.

I understand Zotero 7 is still in development, but I hope these performance and memory issues will be addressed. Thank you.

Here are some of my system details:
Operating System: Windows 11 23H2
CPU: AMD Ryzen 7 6800H with Radeon Graphics
RAM: 16.0 GB

dstillman

You should test with all plugins disabled.

jorathan

Yes. I tested it with plugins enabled and disabled. For the same pdfs, Zetero 6 needs about 300MB while Zetero 7 consumes about 1GB.

dstillman

Did you restart Zotero after disabling plugins?

Zotero 7's PDF reader should generally use less memory than Zotero 6 — I just tested this with the latest version of Zotero 7.

You can test by restarting Zotero 6 and 7 (you can use the ZIP version of one of them to make it easier to switch between them), opening up a single PDF tab, and checking the memory usage after it settles. If there's a PDF where you're seeing Z7 use significantly more than Z6, provide a link or email the PDF to support@zotero.org with a link to this thread.

The main exception is that, since Zotero 7 for Windows is a 64-bit app and Z6 was 32-bit, we allow more tabs (currently 5) to remain in memory, so if you switch between many tabs, you might see Z7 use more memory. In future versions, we'll be optimizing it to unload tabs more aggressively if your system is low on memory. (Otherwise, there's no real downside to an app using memory to keep things fast.)

Zotero 7 should also be dramatically faster than Zotero 6, so if you're seeing performance problems, there's something very wrong on your system.

jorathan

Thanks for your response and explanation.

I just tested it once again in my computer, opening the same 4 PDFs with Z6 and Z7. I restarted Zetero after all plugins were disabled. Here are the screenshots of Zetero and its RAM consumption.

Zotero 6 (400MB)
https://s3.amazonaws.com/zotero.org/images/forums/u6698472/2b7cfajt5g2609pebulj.png

Zotero 7 (947MB)
https://s3.amazonaws.com/zotero.org/images/forums/u6698472/4deedfz6e9k3loaigcwg.png

I've also confirmed this issue with two of my colleagues. So I guess it may involve more than just my system.

dstillman

But that's not what I said to test. See above for what we need.

Again, Zotero 7 will use more memory for multiple PDFs because it keeps more tabs in memory than Zotero 6 did on Windows (5 vs. 3 on >8 GB machines), which makes switching between tabs faster. So seeing higher memory usage once you've opened a bunch of tabs isn't necessarily an indication of a problem.

dstillman

(Your screenshot also shows Zotero using more CPU, which means either it's using significantly more CPU at idle, which would be something to report, or you didn't let it settle like I said, in which case those memory numbers aren't comparable even ignoring the number of tabs in memory. The memory usage will generally go back down somewhat after active operations.)

jorathan

I see. So it's probably because Z7 keeping more tabs in memory that Z6. Thanks for your kind and detailed explanation.

I appreciate your efforts to improve tab switching speed, but its cost is rather a little high for my computer. While my RAM is enough for Z7, I've encountered stuttering on my computer.

It's great to know the team's planing to optimize memory usage in future versions, as I'm sure there are still many users out there whose computers aren't the most powerful and would benefit from better memory management. Thank you!

dstillman

I appreciate your efforts to improve tab switching speed, but its cost is rather a little high for my computer. While my RAM is enough for Z7, I've encountered stuttering on my computer.

This doesn't make sense, though. Using more memory to keep more tabs loaded shouldn't cause stuttering unless you're actually running out of RAM for your open apps — it's the opposite. And there's no change in behavior for computers with <=8 GB of RAM. Again, Z7 should be faster and smoother than Z6 in essentially all respects.

If you're seeing performance problems you don't see in Z6, can you make a video of what you're seeing and either link to it here or, if it contains private info, email a link to support@zotero.org with a link to this thread?

jorathan

Sorry for not making it clear. Normally, I will not run out of RAM, but it's already above 90% when using Zotero and other softwares that I need. So an increase of RAM, for example, when switching tabs or opening more tabs, may cause zotero running slowly or even stutter.

friedsoap

Hi,
I am experiencing the same issues on a Linux machine with 16 GB RAM.

in my case, Zotero, Libre office, Chrome and R are the programs that consume most RAM.
I use Zotero for research and keep many open tabs. I sometimes have to close it down and open it again to free some RAM, when researching, bc that is the less distressful option. I do that bc getting to the limit of RAM induces increased swappiness.

Would it be possible to add an option, e.g. like Chromium, that frees up memory from inactive tabs after a certain time? (I noticed that when I restart zotero opened tabs that are not "visited" do not require that much RAM consumption, which is somehow the same)

Or make it possible to chose btw keeping tabs in RAM or needing full reload, so as to reduce this issues?

Or maybe a button to flush the ram for all tabs except the one opened?

Thanks.
Aleix

ankitp94

I am also seeing a large memory use. Upwards of 3-4 GB RAM memory usage with tabs open while scrolling a small pdf (less than thirty pages).

I am seeing such a high memory usage in the "Troubleshooting Mode" too.

I am using Fedora 41 with Zotero 7.0.13 (64-bit), installed from the tar file.