Until motherboards with chipsets able to use the new DDR RAM, Intel Pentium 4 processors could only use Rambus RAM, which runs at an effective speed of 400MHz, and is comparatively still very expensive compared to standard PC 100 and PC 133 SDRAM, and PC 1600 and PC 2100 DDR RAM. - See below for the news that has just come out that VIA has developed a chipset that supports DDR SDRAM.

AMD Athlon processors can run on motherboards that use PC 1600 and PC 2100 DDR RAM. AMD Duron processors run on a 100MHz system bus that can only use the PC 1600 DDR RAM. PC 2100 DDR RAM runs on a 133MHz system bus. - More on this further down the article.

Below is a table that provides some interesting information about the differences between recent types of RAM technologies.

The table below shows the history of RAM since 1987. The PC66 to PC133 in the three purple rows refers to SDRAM. Rambus RAM is shown in the two yellow rows, and DDR RAM is shown in the three blue rows. FPM and EDO RAM is no longer manufacturerd, but it was used for nearly a decade, and was usually supplied in the form of SIMM modules. Towards the end of its life, EDO RAM could be purchased in the same DIMM module form as DDR RAM.

256MB RAM - minimum on a new PC

You should not purchase a new computer that comes with less than 256MB of RAM. Especially if the video card is built into the motherboard and shares the system's RAM. (A PCI/AGP video card has its own RAM.) If you purchase a computer that only comes with 128MB of RAM, you will have to upgrade it to at least 256MB in order to be able to run Windows XP and the latest games and applications comfortably.

DDR SDRAM and Rambus RAM -- What is RAM and what does it do? -- Which DDR RAM? -- How to install RAM? -- How to identify the size of RAM modules? -- Different types of RAM? -- Mixing brands can often cause problems -- Memory Frequently Asked Questions