My MB can handle P4 800FSB so if I get a 2.8ghz/800FSB will it read
"800" then?
Nope, 200MHz, which is the actually clock frequency in an 800MT/s bus
speed P4.
Can you give me a link or something for your info?
Here ya go:
ftp://download.intel.com/design/Pentium4/datashts/30235101.pdf
Ok, maybe a bit wordy for what you were looking for, but in particular
look for the differences between the BCLK and FSB frequency. Also
this little blurb from the introduction:
<quoting>
"The processor’s Intel NetBurst microarchitecture FSB uses a
split-transaction, deferred reply protocol like the Pentium 4
processor. The Intel NetBurst microarchitecture FSB uses Source-
Synchronous Transfer (SST) of address and data to improve performance
by transferring data four times per bus clock (4X data transfer rate,
as in AGP 4X). Along with the 4X data bus, the address bus can deliver
addresses two times per bus clock and is referred to as a
"double-clocked" or 2X address bus. Working together, the 4X data bus
and 2X address bus provide a data bus bandwidth of up to 6.4 GB/s"
<end quote>
What they do with the P4 bus is actually the same thing as what is
done for AGP4x mode. First off there are two separate signals being
sent over the same pins, each being offset 90 degrees from one
another. Then they send data using both the rising and falling edge
of the clock cycle on each of those signals. The end result is that
with a 200MHz clock you are transferring 4 bits of data on each pin
and for each clock. The result is 800M transfers/second (ie the
800MT/s mentioned above) using a 200MHz bus.
Really stupid if
they put 533 on the actual package, how can they get away with that?
How does Intel get away with this? Well they're only stretching the
definition of "MHz" by a small amount and everyone else in the
industry does the same thing (AMD's "200MHz" to "400MHz" bus on their
Athlon/AthlonXP processors actually run at 100MHz and 200MHz
respectively but sending data on both rising and falling edges of the
clock to get 200MT/s and 400MT/s). Compared to the sins that
marketing departments usually get away with, this one is a rather
small deal.
