HI... I know WIN XP is super outdated, but it's what we have to use. I'm trying to run some 3D scanner software on a new(ish) MacPRO tower (2012 -2 x 2.4 GHz 6-Core Intel Xeon with 32GB RAM). We've run this combo in the past (with Parallels 6 and XP) on an old iMAC and every worked fine. Now that the iMAC has died, I moved this software over to the big boy, upgraded to OS Yosemite running Parallels 11, and my Win XP is telling me that I only have 2.8GB of Ram running in that VM. I've allocated 16 GB of ram to my VM through the Parallels software config, but the end result is always only 2.8GB when checking my XP properties. What am I missing? Surely I don't HAVE to buy more new software to get this stuff to run. There's got to be a solution using what I have, as it has worked in the past. Any and all help is greatly appreciated, as I need to get this scanner running completely. It crashes because I cannot get enough RAM to run. Many thanks in advance; Ken
Hi, A 32-bit OS uses 32-bit virtual addresses. That limits it to 4GB of addressable virtual memory at any one time. If a 32-bit OS also uses 32-bit physical addresses, it is limited to 4GB of physical memory as well. PAE allows a 32-bit OS to use 36-bit physical addresses, which raises the limit to 64GB. Note that memory on our graphics cards DOES NOT COUNT towards the physical memory limit because it does not occupy address space as seen by the CPU. However, hardware mappings do. A graphics card with 2GB of memory on it will probably not have more than 256MB of mappings if the BIOS has memory remapping disabled (which it should for a 32-bit OS). That's why the physical memory limit is typically around 2.8 GB, even if you have a assigned video memory of 1GB -- hardware mappings seldom exceed 768MB.
