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Old 03-03-07, 11:06 AM   #11
Rytr's Avatar
Join Date: Jul 2003
Location: River City
Posts: 1,726
Default Re: How much RAM can XP actually use?

Originally Posted by hokeyplyr48
can vista 32-bit recognize all 4 gigs, or does it have the same problem?
Probably limited to around 3GB. I have not tried 4GB with Vista yet so I don't have any results for mine but I would think it would be about the same as I experienced in XP which was up to 3.3GB. Note the following which I pulled off the net some time ago...don't remember where but it gives the general explanation.

"The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for today’s high performance graphics cards which need addresses for at least the amount of memory on the graphics card. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated."
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