Choose correct RAM to upgrade PC?

Infopackets Reader 'Ppeltscott' writes:

" Hello! I have an HP pavillion model number 743g and it has 512mb of DDR memory [RAM]. I was just on Hewlett Packard's web site to see how much RAM I could put in my machine, and it said that my particular model uses 3 different RAM types: 200mts, 266mts, and 333mts. Does this mean that I can use the 333mts [PC2700 DDR] instead of the 266mts [PC2100 DDR]? Thanks for any input. "

My response:

The short answer is that you need to match the existing type of RAM inside your machine. A very simple way to find out the speed rating of your current hardware configuration is to use a freeware utility called WCPUid (link to follow).

The long answer:

The numbers 200, 266, and 333 that you mentioned above refer to RAM speed rating. This rating is related to the Front Side Bus (FSB) speed of your processor. In short, FSB is the speed at which all components inside your computer communicate with one another.

Quite often, the FSB speed rating of a processor is overlooked. Lower end processors such as the Intel Celeron use slower FSB speeds (compared to a Pentium 4 counterpart) and cost significantly less. For example, a Pentium 4 2.0 GHz will outperform a Celeron 2.0 GHz processor simply because the FSB speed ratings are much different (400~800MHz compared to 66~133MHz FSB).

If you have DDR 333 RAM inside your machine now and you install 200 or 266, your computer may not work properly (if at all). This is because the motherboard must be configured to run the processor and RAM at the designed speed [system clock x multiplier = processor MHz].

To find out your the FSB if your hardware configuration, you can can download a freeware utility called 'WCPUid'. Hint: Look at the "System Bus" rating. The latest version of WCPUid is 3.1a according to the author's home page (H. Oda), dated 2002/12/22. If you have trouble downloading from that web site, you can also grab version 3.1a from infopackets.com:

http://www.infopackets.com/dloads/wcpu31a.exe

Side Note: When you install the program, it will ask you where to decompress the files. Choose a location which will represent where this program is to be stored on your computer; the program itself does not use a setup.exe utility to install onto your computer.