What The Heap?

64-bit versions of Windows XP and Vista allow 64-bit applications (such as SolidWorks) to access memory above the "3GB barrier" that's hard-coded in good ol' 32-bit Windows. If you're running out of memory, you already know that SolidWorks and Windows itself give you warnings to that effect.

What is generally known is that even if you never work on large datasets, you can still have problems in 32-bit Windows. Not because you're running out of memory overall, but because you're exhausting your "interactive heap memory."

Every time you do something in a Windows program, you have objects like icons, tabs, and the like that have to be loaded into memory. It doesn't matter if it's a big program like SolidWorks or a simple program like Internet Explorer -- they all eat away at the memory allocated for handling those things. Unfortunately, 32-bit Windows XP Professional -- by far the most prevelant operating system on corporate desktops today -- has a limit of 3MB (yes, that's megabytes, not gigabytes). When this is exhausted, any command that will open up a new menu, dialog box, tab, etc. will cause the unsuspecting program to crash.

How does this manifest in SolidWorks? Crashing when editing a dimension, putting on a mate, or basically anything that opens up a new window or object on the screen. They can appear to be totally random crashes. You will see this window pop up:

   

So how do you increase your memory allocation 32-bit Windows? You don't -- it's hard-coded in the OS.

It's another example of an OS living longer than it's intended time, changing technology and user demands on their software and hardware. It's another barrier that is hard-coded and cannot be changed. It's also another great reason to make the move to 64-bit Windows, where running out of interactive heap memory isn't a problem.

I'm not a spokeperson for 64-bit Windows, just a satisfied customer :)

Comments

[Frank Dijkstra]

i'll agree to that, i get crashes like those about every 2 hours, plus an additional kind of crash saying i have no memory left to do stuff, making SW crash.
i'm already urging our pc-guy to make the switch asap :/

[Jeremy]

We are running 64 bit Windows XP and SW 32 bit and still see this error on a regular basis. Is it required that you switch to SW 64 bit as well or are we getting this error for other reasons?

[Mikka]

Increase you heap...
http://support.microsoft.com/kb/126962

[Jeff Setzer]

Hi Jeremy. Running a 32-bit app under 64-bit does not allow the app to access memory beyond 4GB. You need to run the 64-bit version of SolidWorks under the 64-bit version of Windows to break the 4GB barrier.

[Scott Biba]

I had similar problems (32 bit) and fixed it by increasing the "shared section" yyyy value from 3072 to 4096 in the registry. Not hard to do. haven't had any trouble since.