Many thanks!
Apologies for my ignorance on this issue - but does
mean that it is a 333 MHz FSB? Or is there a different interpretation of FSB
values for AMD chips (as in the CPU labeling)?
The Athlon uses a DDR bus, so it's effective data rate is twice the
clock speed. The chip uses a 166MHz bus speed, but because it's DDR
the marketing folks always (incorrectly) say that it uses a "333MHz"
bus, just like they incorrectly state that the newest Pentium4's use
an "800MHz" bus.
It's kind of like when people used to say that they had a 9600 "baud"
modem. The "baud" rate, or symbol rate of those modems was only 2400
symbols/sec, but people were still using outdated terminology from the
300bps modem days (a 300bps modem ran at 300 baud). Proper
terminology for the modem would have been "9600 bps" (bps = bits per
second).
Similarly, proper terminology for the Athlon's bus speed would be
333MT/s (millions of transfers/transactions/transitions/t-whatever per
second), or perhaps more importantly, 2.7GB/s.
Or is 333 (or 400 in 400 FSB case) always 166*2 or 200*2 and hence the name
Double Data Rate for RAM ?
In the case of DDR memory and the Athlon's DDR bus, yes. The first
few Intel Pentium4 chips used a 400MT/s bus that ran at 100MHz QDR
(QDR = Quad Data Rate, similar concept to DDR except sending 4 bits
per pin per clock tick instead of just two).
)