Steffen you pose some interesting questions. Let me expand them a bit.
i.e. The Intel is labeled 3GHz but I know they lie as experienced in the
front side bus?
Answer: Yes they really have something running in there at 3GHz... but
not for long. Rival chip maker AMD has long used system numbers like
3000. They define this as their CPU producing the same number of mips
(machine instructions per second) as an Intel equivalent running a CPU
clock of 3GHz. This is because AMD gets more mips per clock than Intel
does. Bottom line is the AMD 3000 is running somewhere around 2.5GHz.
Since chip dissipation is directly related to clock speed, AMD builds a
cooler chip than Intel by running a slower clock.
Both AMD and Intel throttle down the clock when idling to save power.
This may explain why you can't see a large spectral content at 3GHz.
Intel has recently announced they are adopting a rating system like AMD.
Both AMD and Intel are coming out with 'dual core' chips. Using a
similar rating system two 2000s (i.e. dual core) are rated as a 4000 but
running much, much cooler.
Regarding the physics of the transistors the processor are really
running f sub t of > 20 GHz. They get the speed as a by product of their
die shrinks. That's why they are working at .2 micron and below. Lots
of bandwidth when the geometry is so small.
Fred Townsend
Steffen Maisch wrote:
Hello!
I ask this just, because I'm curious:
When Intel is saying e.g., their processor is running at 3000MHz, what does
this mean?
Is there really any digital signal inside at that frequency, and a PLL that
locks it to the in/out frequencies?
I know, if they say, there front side bus operates at 800MHz, it's only
200MHz. Then they just multiply it by 4, because it's 32bit. But I cannot
compare anything to vintage 8bit processors, so that doesn't make much
sense.
The second thing is: Processors are advanced thechnology. But could it be
possible to have these speeds for a digital circuit, which means, a
transition frequency of >10GHz to remain any waveform other than a pure
sine? If I try to make a circuit with a simple 1stage transistor amplifier,
I'll use the most expensive III-V-HEMFET for 10GHz, and it's still a
challenging task, and power below 10W; and they can do this with >100 000
000 silicon tansistors, 100W of power, on a single chip for $250?
I ever tried to wind a wire loop around a running procesor and connect it to
a spectrum analyzer. But you can see anything from nearly dc up to the max
freq. of the analyzer. No strong peak at the declared frequency.
Thanks for your answers!
Steffen
--
Author: Fred Townsend
INET: [EMAIL PROTECTED]
Fat City Hosting, San Diego, California -- http://www.fatcity.com
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB CHIPDIR-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
