What’s happened To My RAM?

Posted by Aleksandr Rogers

May 8

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As operating systems and software applications get bigger and bigger, we often find that we need to install more system memory (RAM) in our PCs. Worse still, we may find that our PC motherboard won’t support any more, so we need to upgrade that, too.

So we head down to our local computer store and the salesman convinces us to buy 8Gb of RAM, and maybe a new motherboard in which to install it.

Back home, upgrade completed, we power up, expecting our operating system and software to luxuriate in the relative ocean of 8Gb of memory.

But wait! What’s this? Windows tells me I have only 4Gb of memory. Is the memory I bought faulty? Have I installed it incorrectly?

So we go through the futile cycle of opening the box, re-seating the RAM in its sockets, trying just one 4Gb DIMM at a time and so on.

Still, Windows reports only 4Gb. So we boot up into the PC’s BIOS. It says 8Gb in there, so what’s going on? Is there a BIOS setting that I need to change for Windows? No, there isn’t.

So what is going on?

The chances are your version of Windows is 32-bit. If you’re not sure, it’s one of Vista, Windows XP or maybe Windows 2000. (Windows 98, anyone?)

The number of “bits” determines the amount of memory that can be addressed by the computer or operating system. As “bit” relates to binary, or base 2, numbers, to determine the maximum amount of memory addressable by a 32-bit system, we have to multiply 2 by itself, 32 times. So we get:

2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 4,294,967,296

And 4,294,967,296 bytes = 4 Gigabytes.

Therefore, Windows can not recognise more than 4 Gigabytes of memory.

So if you’ve been convinced to upgrade to 8Gb, you’re going to be disappointed. Take it back to the store and get your money back.

The only way you’ll be able to use the full amount is to upgrade your operating system to a 64-bit version of Windows.

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