Since he's running XP32 and has 4GB, then he's really only getting the use of 2GB unless he has the /3GB in his boot.ini as 3GB is the maximum addressable memory that XP32 can handle. Using 2GB as a ramdrive and putting his swapfile or as the system temp folder is a good use of memory sitting around doing nothing.
Microsoft's Answer
Ummm no. Read it again, you're getting confused between an applications virtual address space, and the addressable memory of the system. The /3GB applies to the 4GB (virtual) address space allocated to *each* application. Normally this is split 50/50, which means 2GB is allocated for system use, and 2GB is allocated to app use. However, you can run more than one application (obviously) on your system, which means the system as a whole can use more than 2GB even on Windows 32-bit, up to what the system can address.
Now, Windows 32-bit XP can address up to 4GB of physical memory. Of that, something around 3.2GB - 3.5GB will be *usable* by applications (and, by default, as per the above, up to 2GB per application.) If you add the /3GB switch, then that affects the application virtual 4GB address space, which splits it into 3GB/1GB, and will do nothing to help you address more memory from a system wide perspective, that is still limited to 4GB. The simple fact is, the system can address up to 4GB, from which is subtracted address ranges for things like:
* System ROM
* APIC(s)
* Integrated PCI devices, such as network connectors and SCSI controllers
* PCI cards
* Graphics card
* PCI Express cards (if applicable)
Thus, the RAM usable/visible by the OS will therefore in reality depend on the hardware you have installed on your machine. And as I say, typical values today is around 3.2GB up to about 3.5GB usable address space (and consequently RAM, if you have that much RAM in your machine.)
Now, all of this has
nothing do do with the original posters question,
as any RAM drive he creates, must come out of the possible usable 4GB addressable space, if running under Windows XP 32bit. In fact even worse, if it's a normal application, your RAM drive app can only allocate itself up to 2GB of memory, limiting the maximum size of the RAMDrive!
Now the only exception here, as per the page you cite, is *IF* and only if, he runs Windows Server 2003 Enterprise or Datacenter editions
with PAE extensions then he can use up to 32GB or 64GB of RAM respectively. This is a bit like XMS was in the days of the PC/XT, where RAM is paged into the possible address space in chunks etc. Not really nice. It was a stopgap solution prior to the release of proper 64-bit versions of Windows.
I thus re-iterate, there is no benefit to be had, from creating a RAM drive with the idea of swapping to it and particularly not on Windows XP 32-bit.
