[Bf-committers] Re: Windows (XP) refuses to allocate > 1 GB

GSR gsr.b3d at infernal-iceberg.com
Fri Jun 30 19:24:21 CEST 2006


Hi,
joeedh at gmail.com (2006-06-29 at 2115.47 -0700):
> Ton Roosendaal wrote:
> > See the thread here:
> > http://projects.blender.org/tracker/?func=detail&atid=264&aid=4539&group_id=9 
> > And with some googling I found this:
> > http://www.stata.com/support/faqs/win/winmemory.html
> >
> > Apparently XP with SP2 refuses to give larger blocks than a gig. With 
> > our floatbuffer approach that limits rendering to a resulution of 
> > about 6000x9000 pixels.

I remember someone had a similar issue (big mem usage), in which same
computer managed to render fine when running Linux but no when running
MSWindows, even a just rebooted one. I think changes to Blender (the
mmap?) made the scene not stress memory fragmentation. I tried the
scene myself, and the peak was around 900MB IIRC.

> According to MSDN, there is a group of functions for accessing > 4 GB, 
> documented here:
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/memory/base/address_windowing_extensions.asp
> 
> But I have only 755 megs of memory, so I can't really test it.

It does not matter as what you found seems to be for the "more than
4GB installed in a 32 bit Intel CPU" hack called PAE (Physical Address
Extension) based in segmentation but still using 32 bit pointers. In
other words, you need a CPU with PAE too (Xeons of some years ago)
while sane people just get 64 bit CPUs now (AMD or Intel).

So indeed, if there is a need for a fix, then it should be in the way
of spliting big blocks of mem if possible, it would help any OS.

GSR
 


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