Spec question

[Rolen27]

It's been a while since I've payed attention to the specs for computer parts. The specs for CPUs and memory have me confused. I know what a bus speed is. I know how the CPU speed is calculated. What confuses me are all these numbers in parentheses. Like an Athlon XP 2200+ (266MHz). At first I assumed that 266 MHz was the bus speed, but I've seen some websites state that the bus speed is 133 MHz (with a multiplier of 13.5).

I'm also confused on RAM specs. It's pretty much the same question, though. Are bus speeds at 200+ MHz now? The last system I built was had a socket-7 board with a 100 MHz bus speed (ya, I know that was a LONG time ago).

If someone could enlighten me, I'd greatly appreciate it. Thanks.
Go Cards!!!

 

[Col_Kiwi]

The CPU you're looking at has an external frequency (or system bus, or FSB) of 133MHz. the 266MHz is the CPU bus (or CPU data bus) of 266MHz. This means that the data bus uses DDR (Double Data Rate) technology, meaning it performs two instructions per cycle. Hence, the "<b>effective</b>" bus speed is 266MHz, with an actual frequency of 133MHz. Make sense?

RAM speeds work similarily. the most common type of RAM for an athlon platform is DDR266 (aka PC-2100) which is 133MHz but uses that same DDR technology i mentioned before for an effective clock of 266MHz. the PC-2100 means approximately 2100MB/s transfer rate.

Other types of common DDR ram:

DDR200 (100MHz; PC-1600)
DDR333 (166MHz; PC-2700)
DDR400 (200MHz; PC-3200)

The formula is the same for all the other less common types.

There's also RAMBUS memory which is another story, but thats on Pentium 4 platforms only so I'll spare you the explination if you're looking at athlon anyway.

-Col.Kiwi