Ram Question

[zocheyado]

Tried looking around but couldn't find exactly what I was looking for, If I installed a 64bit OS, say a linux distro, or windows 7, and i have 8gb of ram installed on that system, THEN if I ran a virtual box of windows xp 32 bit version, could I access all 8gb of ram on the windows xp virtual machine?

[vbox4me2]

No, the Host must see all ram you want to give to a Guest.

[zocheyado]

I know, im saying if my main os is windows 7 64bit with 8gb of ram, with that allow me to run a host windows xp 32 bit at more then 3.2gb of ram

[stefan.becker]

Its a problem of XP, not from VBOX.

[mark rumsey]

32bit Windows is what sets the 3.2Gb limit. 32bit operating systems have an absolute limit of 4.2Gb and Microsoft decided that nobody would ever use that much, so they reserved the addresses from 3.2Gb upwards for system use. As a result all NT based windows OS's cannot access any memory above 3.2GB. You could allocate more to the VM, but it would be wasted as the XP guest would only be able to use the first 3.2Gb of it.

[vbox4me2]

Correct and yes there are workarounds to get a 32bit OS to see and use up to 32gb of ram, the problem are OS drivers and the software run on it, most 32bit drivers can't handle this and will crash the system, even the most common drivers such as the login process can cause this.

[mpack]

My XP Pro 32 bit host has 4GB RAM installed, 3.46GB available. Right now with Firefox 6 running, task manager tells me it's using 185MB of that available memory (and that's with the paging file disabled, so all memory comes from physical RAM). If I had four or five more apps open, I might reach 1GB committed. Hence I struggle to understand why anyone would want to assign more than 4GB to a 32bit OS, even if it were possible.

[vbox4me2]

Database engines and ERP packages are always looking for more ram. Two of them could each use 3.5gb ram on one 32bit OS if the ram was visible.

[mpack]

A quick "back of the envelope" tells me that 1GB of RAM is enough to store ~52secs (1294 frames) of uncompressed PAL SD color video. I find it hard to imagine applications for typical users whose RAM demands are worse than that! (and in any case a home video editor would rarely need to have that many frames resident in memory at once). Databases in particular shouldn't need anything like that amount of RAM (disk space is of course a different story). Efficient indexing algorithms for databases have been known since the '60s. People mention CAD as another example, but again I don't see how a vector graphics CAD model - even 3D - would compete in terms of RAM demands with a 3D raster image! (i.e. video).

ps. I'm not familiar with the "ERP" acronym.

[vbox4me2]

Then you should get more familiar with such platforms, Autocad for example can easily use 8-32gb of ram not just for rendering, look at Revit and Wafs implementations that skyrocket in ram usage. When it comes to databases you really need to get up to speed, no optimization can beat a 32gb database completely loaded into ram and there are TB db's out there. ERP reporting are usually complex queries over many if not all tables with inner and outer joins passed to stored procedures and back again for which no storage pool is happy with considering the amount of IO. I've seen a DB driver that can access the area between 4 and 12gb on a 32bit OS bypassing the OS restriction. But then again x64 is gaining ground fast making such discussions moot.