Iphone

Reader Gary Priester has a question likely to be faced by other buyers of computers outfitted with Vista, the latest Microsoft (MSFT) operating system:
I just purchased a new Dell [computer] with Vista. I ordered 4GB of RAM and a 320GB hard drive. When I first booted the machine, it showed only 3GB of RAM and a 288GB drive.
After much going back and forth with Dell (DELL), both on the phone and via e-mail, finally one of the tech-support persons explained that the difference is Vista uses binary to measure memory, whereas the traditional way is to calculate by the decimal equivalent.
It made sense, and they have a chart hidden somewhere deep in the bowels of their Web site that shows the equivalents. This is probably something that should be pointed out to consumers in the first place and would have saved Dell and me a lot of time.
Dell's explanation may make sense, but it doesn't answer your memory question. Yes, what we commonly refer to as a megabyte (1 million bytes) of memory is actually 1,048,576 bytes. But that isn't the issue here.
The confusion may be related to a somewhat obscure issue called memory addressing. Until recently, Windows and the hardware it runs on have used 32-bit addressing. This limits total memory to what can be represented by a 32-bit binary number, a bit more than 4 billion bytes. Your new computer almost certainly came with the 32-bit version of Vista. Although there is a 64-bit version, it's not being used much because it has, to now, extremely limited support for third-party hardware.
And if your computer is a laptop with an Intel (INTC) processor, the chip that handles memory addressing, known in computer-speak as the northbridge, can only handle 32-bit addressing, even though the Core Duo and Core 2 Duo chips themselves are 64-bit models.
This limits you to 4GB of physical memory. But the available user memory is less than that (3GB in your case) because the system reserves a chunk for its own use. Click here to read a good Hewlett-Packard (HPQ) paper on the issue. While it deals with Window XP, it's equally applicable to Vista.
New Chips on the Way

Traditionally, memory modules grow by powers of 2, so you can buy 512MB, 1GB, or 2GB. And the Core Duo architecture requires that memory modules be added in matched pairs.
Later this spring Intel begins shipping new chips, code-named Santa Rosa, that will allow full 64-bit operation, as is already possible on Intel and AMD (AMD) desktops. With luck, by that time Microsoft and third-party software and hardware vendors will have added enough support to make 64-bit Windows a more useful proposition.




Source:Vista PCs: Suffering from Memory Loss?