dk_ said:
Here's some numbers from an advertisement from e-machine's site...
"AMD Athlon 64 3200+ Processor (512KB L2 cache, 2.2GHz, 1600MHz FSB)".
The numbers show an FSB speed, (which is much faster than what is
advertised in an equivalently priced Celeron D machine.
That's a "little white marketing lie". Since most people are used to
seeing a FSB speed rating, Emachines just took the closest thing they
could find to a front-side bus, which is the Hypertransport link, and
called it the FSB. The more proper answer to what is the FSB speed of
an AMD64 processor would be "not applicable", but of course that would
generate questions like "why is it not applicable?", or "if it doesn't
have a FSB, then how does it work?", etc.
The Hypertransport link does fulfill one of the functions of the
traditional FSB, which is that it connects the i/o chipset to the CPU.
However, the memory controller is not on the i/o chipset like with
Intels, the memory controller is inside the AMD CPU, so the only job an
AMD i/o chipset does is interface with peripheral devices like video
cards, hard disks, USB, etc. The AMD memory controller is not part of
the Hypertransport connection, it is its own independent connection.
That's why AMD has coined the marketing term "Direct Connect
Archictecture" to describe the combination of its internal memory
controller, and the Hypertransport link.
Also Hypertransport is not a bus in the strict sense of the word, it is
a point-to-point link, i.e. one-to-one only. Secondly, the speed rating
given to it in the ad, "1600MHz FSB", is just a maximum possible speed;
the HT link being point-to-point is a negotiated speed. So it only
connects at the highest speed common to the CPU and the chipset it is
connecting to. If the chipset can only go as fast as 1066MHz, then
that's the speed of the HT link that they will negotiate.
Yousuf Khan