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Laptop Memory -- More Is Better

laptop ram

When you look at the laptop memory listed in an add for a laptop computer you are thinking about buying, you will see a number usually labeled GB and probably DDR2. This tells you how much laptop memory you have and that it is second generation DDR memory.

This doesn't tell you much really, especially since the memory is one of the few user upgradeable components of a laptop computer.

Here is a break down of what you might see in modern notebook ram.

Standard Name	I/O Bus Clock	Module Name	Peak Transfer Rate
DDR2-400	200 MHz	PC2-3200	3200 MB/s
DDR2-533	266 MHz	PC2-4200 or PC2-4300	4266 MB/s
DDR2-666	333 MHz	PC2-5300 or PC2-5400	5333 MB/s
DDR2-800	400 MHz	PC2-6400	6400 MB/s
DDR2-1066	533 MHz	PC2-8500 or 8600	8533 MB/s
DDR3-800	400 MHz	PC3-6400	6400 MB/s
DDR3-1066	533 MHz	PC3-8500	8533 MB/s
DDR3-1333	667 MHz	PC3-10600	10667 MB/s
DDR3-1600	800 MHz	PC3-12800	12800 MB/s

Different modules names are listed because different manufacturers round (and name) differently.

DDR-3 memory uses less power than DDR-2 memory and is more expensive.

The memory modules come in different sizes. They will be 256 MB, 512 MB, 1 GB, or 2 GB. Each larger module is twice the size of the smaller one. Generally, 2 smaller modules cost less than one of the next larger size.

Most of the time you don't have much choice about what laptop memory upgrade can be put in your computer after you buy it. The motherboard controls this. Manufacturers generally provide you with minimums as the standard components in a laptop computer. The bus speed of the motherboard will be what is required for the processor you have selected. The memory will be DDR2 memory at or below the speed of this bus. All the memory slots on the motherboard will be filled. This is the least costly way for the manufacturer to make the computer. If you are buying at the bottom of a line of computers where there is a large range of processors available you may have a choice of different memory types because the different processor bus speeds.

Your operating system may recognize only a limited amount of memory. 32 bit Vista will recognize about 3.3 GB on system memory and an additional .7 GB of video memory.

Unless you are at the upper level of laptop computers your motherboard probably will not support DDR3 memory. If it does, they will probably try to sell you it. If you spend more, the total profit is greater at the same profit margin.

Again, more is better and faster is better within the limits I've described. Remember, if you mix and match everything runs at the slowest speed.

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