Many users of desktop operating systems have been happy with 512MB, 1GB and 2GB memory configurations. As memory prices continued to drop it was typical to see someone bump their memory from 1GB to 2GB. Many laptops have been sold with 2GB RAM configurations. Considering the cost of a 2GB SoDIMM, this was a reasonable trade off.
Now that laptop memory has started to become even more affordable, loading up a laptop or desktop with it's memory capacity seems to be in vogue. For most desktop and laptop configurations, this means 4GB of memory. The thinking is that the added memory will improve performance and provide a better user experience. The problem is, that most people are in for a rude awakening when they do this.
A recently published support article at http://support.microsoft.com/kb/929605/en-us does a great job of describing the issue. You'll also notice in the article, that various chipsets supporting 4GB and higher are documented. Here's the punch line from the article:
For Windows Vista to use all 4 GB of memory on a computer that has 4 GB of memory installed, the computer must meet the following requirements:
- The chipset must support at least 8 GB of address space. Chipsets that have this capability include the following:
- Intel 975X
- Intel P965
- Intel 955X on Socket 775
- Chipsets that support AMD processors that use socket F, socket 940, socket 939, or socket AM2. These chipsets include any AMD socket and CPU combination in which the memory controller resides in the CPU.
- The CPU must support the x64 instruction set. The AMD64 CPU and the Intel EM64T CPU support this instruction set.
- The BIOS must support the memory remapping feature. The memory remapping feature allows for the segment of system memory that was previously overwritten by the Peripheral Component Interconnect (PCI) configuration space to be remapped above the 4 GB address line. This feature must be enabled in the BIOS configuration utility on the computer. View your computer product documentation for instructions that explain how to enable this feature. Many consumer-oriented computers may not support the memory remapping feature. No standard terminology is used in documentation or in BIOS configuration utilities for this feature. Therefore, you may have to read the descriptions of the various BIOS configuration settings that are available to determine whether any of the settings enable the memory remapping feature.
- An x64 (64-bit) version of Windows Vista must be used.
Like I mentioned in some previous articles, the desktop and laptop configurations coming in a few months will be specifically designed to support 8GB of memory. So should you upgrade your memory right now? If you have some available memory slots and are sitting at 512MB or 1GB of memory, then the answer is probably yes. This will certainly allow more head room for Windows XP and of course any upgrades to Windows Vista will be happier as well. I would not consider going above 3GB on a laptop or desktop until you've confirmed support for 4GB of memory. If on the other hand you don't have any available slots, then the decision gets even tougher. It would mean pulling existing working memory for newer higher capacity memory. I really hate to do that. You end up having a memory grave yard like I do.