I often work with 50MB+ .ai files and sometimes my computer runs slowly because there's a ton of vectors, so it has to render them everytime I navigate through the file.

Is it true that using symbols would reduce resource usage (CPU and RAM) as a symbol works as a symlink (reference to another file/resource)?

Thank you!

  • If there is duplication then the file size will be lower. But it will not make your file any faster (unless your running out of memory, in which case its just cheaper to buy more than complain. Eveb though memoru is all time high in price).
    – joojaa
    Commented Apr 25, 2018 at 15:33
  • if AI works in any way similar to game rendering (plausible with GPU acceleration), then symbols are probably a form of instancing where the symbols is queued up alongside a list of transforms (size, positions, etc) and then batched in one "draw call" (or similar). An individual "Draw call" has overhead, and rendering 20 identical objects (with minor transforms) each in a "draw call" is slower than instancing.
    – Yorik
    Commented May 25, 2018 at 18:48

1 Answer 1


The developers of some of the hands-down best Illustrator plug-ins out there, Astute Graphics, certainly seem to think symbols help manage file size in vector-heavy files:

"Vector artworks can contain multiple objects or groups of objects resulting from duplication. In this case, save the item that you want to duplicate as a symbol in the Symbols panel (Window > Symbols). Then proceed to the duplication character, for example, using the Symbol Sprayer Tool. Using symbols greatly reduce the size of the original file. Their use is particularly justified if you want to duplicate complex objects."

From: 9 ways to minimize file size adobe illustrator

But in that same article they give a lot of other useful filesize tips (worth a read) including one I know helps a lot: uncheck the PDF-compatible file checkbox when saving your AI, and check compression - this will save you in many cases >50% file size. If it's required that you save a PDF compatible AI later for collaboration, you can do that in a separate save-as - work compressed as much as you can and it will help.

I have to work in huge illustrator files frequently when working for some architecture firms (100+ Mb illustrated site plans) and can say that once they get to be unwieldy, I tend to work in outline mode most of the time for that same reason - no point waiting for rendering of complex transparency and shadow effects on the trees as I scan and pan, if I already know they're correct and now I'm working in another layer adding the hardscape or entourage.

  • 1
    You can actually rasterize layers at low res with effects for faster performance ;)
    – joojaa
    Commented Apr 25, 2018 at 15:35
  • @joojaa - yes indeed you can - good pint and well mentioned - but normally one can only do that with impunity once you know the core design's not radically in flux anymore... which in an architectural workflow isn't until months later in many cases! Commented Apr 25, 2018 at 15:51
  • 1
    The original data is still there you can allways just remove the effect do changes and turn it back on.
    – joojaa
    Commented Apr 25, 2018 at 17:33

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