Is there a maximum size of svg file that Inkscape can handle? I'm using Inkscape r12126-201302142316 (well aware of the fact that this is not offered as a stable version -- but it does have a couple of features that I wanted to be able to use!), and my machine has an Intel Core i7-3820 3.6 Hz processor and 16 GB RAM, running Windows 8.1 64-bit. With normal relatively small files there are absolutely no problems and the program is fast and stable. But I've been trying to work on a large map. The svg file is 7.5 MB, but the memory used by Inkscape when it is open is 440 MB. Responses to any editing change are desperately slow, but the changes do usually work. If I then save the file (without closing), that seems to work. But trying to close the file almost invariably crashes Inkscape, and on the rare occasions that the file will close, trying to shut down the program then crashes it. During actual editing, changing graphics seems to be much more stable than changing text. Since small documents are fine and this largish document is not, all I can assume is that size has something to do with it. So have I run up against some sort of size limit?

It's hard to tell. it depends on the content of your files if there are a lot of filters (blur and so on) it will require more memory.

There is some limitation, probably the unofficial 64bit version could work faster.

What you could try: delete unused defs (file menu, vacuum defs option).
There is some bug about the gradients, that can store each and every modifications of them in separate defs, that can lead to crash.
The pattern fill can also crash the program, if there are too many objects using it, with a relative small svg size too
-that part is handled by garbage collectors, which is not developed by inkscape.

In the preferences, you can change accuracy of the svg -how many digits the data will be stored in.
Reducing it can make work faster, and the file smaller.

Handling of objects: to my experience a path with 10000+nodes can make inkscape struggle and can have rendering issues. But, once broken apart and -preferably- grouped together, it solves the problem.

Thanks for both replies. No filters in use, and no pattern fills. Also no single path anything like as huge as 10,000+ nodes -- rather, a whole lot of very much smaller paths. I suppose it's a typical map. Lines of a couple of thicknesses using half a dozen colours, filled circles as markers of locations, and then text as labels for those locations (and those last two seem to be by far the slowest layers when it comes to re-drawing the screen). I assume 64-bit would let me access all my RAM rather than just 4 GB of it, and that sounds as if it ought to make a considerable improvement. It would be interesting to give the unofficial 64-bit version a try, but I don't think I've found that!

It was compiled by Partha.

Texts can also be "fastened up" once they are converted to paths (Ctrl+Shift+C).
That turns text objects to groups of characters.

It looks as though memory is the problem. With the 64-bit version everything seems to work fine (though a little slowly) and close and exit both seem to work without crashing the program. But despite what the Release Notes page for 0.91 says about a native Windows 64-bit version from Partha, Partha seems only to have 48/4, which is what I've just been trying today. So I'll obviously carry on using that for the map in question, but I'll stick with the pre-release 49 for other things because several of the enhancements are very nice to have indeed (and, from a purely personal perspective, I don't like the very dark theme Partha uses!).

I had similar problems, also with a map. Had maybe 20 layers, but lots of objects and pattern fills. Not a TON of Gaussian blurs, but certaily some, and certainly I over-used some of the (excellent) SVG Turbulence Filters that Inkscape has available. Still, it got to where I was working in Outline Mode on very small sections of the map, saving after EVERY edit, and never knowing when the next crash would come.

Eventually I went to Illustrator CC, largely in the belief that it would be more stable. That part has been true; I very rarely crash with Illustrator, doing similar documents. That in itself has made the transition worthwhile, even though there was a learning curve to be conquered. And Illustrator CC's pricing scheme is certainly more Joe-Sixpack-friendly than it used to be.

That said, it's shocking to see how un-polished Illustrator CC really is. I went to that program thinking it would be this awesome experience honed over the course of 15+ years as the Go To Tool Of Choice For Vector Art Professionals. Ohhhhhhhh no. No no no no NO. Not even close. In many ways, Illustrator CC feels like the Open Source v0.48 application here, while Inkscape is the polished v17 incumbent. There are many things about the Inkscape interface that feel more polished, sensible, and user-friendly than Illustrator. YMMV, of course, but I thought it was a surprising thing worth noting.

If Inkscape can fix the stability issues that you and I are apparently experiencing, then I'll be back in a heartbeat. (Another big needed fix is for pattern fills to tile correctly without lines at the seams, but that's on everybody's wish list). Still, if you're at a spot where you can't move forward, Illustrator CC might be worth considering as a stop-gap measure.