After Effects is giving me this warning: unable to allocate space for a 7200x3902 image buffer. You may be experiencing fragmentation. In the Memory & Cache Preferences dialog box, try decreasing the Maximum RAM Cache Size value and selecting enable Disk Cache option, increasing Maximum Memory Usage or both.
(7::39)

I am on a new MacPro w/ 8g of ram. I've been working on this animation on an imac for a long time so I know that this shouldn't be happening. I got this error the first time I opened this project, and tried to do what it advised. Now it works for a while then gives me the error or fails to render. I don't really understand all this RAM cache stuff, so I wonder what those settings should really be at?

AE wants more memory than you have to process your image.

I usually pre-compose the image and slash the resolution of that comp's settings. Then the the image buffer can be smaller since I'm asking it to run effects on the smaller pre-composed layer.

This project works fine on an old imac though. The MacPro should have no problem with it at all.

UNABLE TO ALLOCATE SPACE FOR A AxB , what do i do about it?

I receive this error occasionally on several systems. The first thing I do is save the project and restart After Effects. If it still doesn't work, I restart the computer. It's always worked after a full system restart.

seems to work fine after the restart !


thanks

Restart doesn't help at all. It seems this is an all too common problem that many people are having, but none of the solutions are very good ones. After Effects advises you to go the AE pref.txt and look for the part that says: "MaxNumberOfProcesses" to change the value to "6".
It doesn't say any of that in my text file, and that's a weird way to fix it anyways.

Render fails on a computer with 8 or more processor cores (After Effects CS3) (http://kb2.adobe.com/cps/402/kb402403.html)

Other sites basically suggest you cripple your computer's RAM usage:

General Specialist: Avoiding the "After Effects error: could not create image buffer" (http://generalspecialist.com/2006/11/avoiding-after-effects-error-could-not.asp)

I'm trying a render with this advice now, but of course it is 10 times longer. So far I've just been sitting around waiting for my renders to fail. Hopefully this starts to make sense to me soon so I can fix it.
AND AGAIN: This project works perfectly fine on a crap imac!

If you haven't already done so, do the most comprehensive RAM testing you can (I'm not a Mac guy, so don't know what utilities are available -- in the PC world, it would be memtest which has saved my bacon before).

Failing any other solution, make sure to file a thorough bug report with Adobe. They are putting out a 4.2 version of PPro soon, so maybe with luck they'll also see do an AE update to squash a few bugs.

I should mention that I read AE CS4 has the ability to not render things that are out of frame. That sounds like an instant fix to the problem. (I am using CS3) I don't know how to test RAM.
The advice in the second link I provided fixed the problem for now, I can't even remember what it was though... messing the cache memory preferences don't mean much to me.

My renders fail, so I've upgraded to After Effects CS4. I'm also using much smaller images now and it has the same problem (on two different pimped out Mac Pros).
I've found in CS4 there is a way to use more CPUs thank god, so I am rendering now -hopefully this will work. By default is uses a puny 1.79 gigs. Only 1 CPU out of 8.

Thats an enormous image for AE. Its a normal issue you're having. If you are still having problems, cut it up into 4 or more different images and pull it in as a PSD comp with the 4 layers. CS4 is better but still sucks for how it handles that stuff. Its not true 64bit until you can only have one instance of AE running using every bit of RAM IMO. Something I've hated too...

I have this problem if I am trying to render too much on the timeline at once. I will then render the bg first then import it and do the rest.
You can also have it turn off caching so that it is forced to render 1 frame at a time. This slows it down considerably but the render completes.
There is a secret option in preferences that allows you to do this.
Hold down shift then select Edit->Preferences and you will see the Secret option. Set caching off and to 1 frame.

However, since you have 8 available cores you might try setting some value less than 8 to see if that helps first.

Jim