where's the multiplier?

i see that new CPUs have the multiplier within. But I recall that old
board had a jumper for setting the multiplier. Am I then right in
assuming that the old CPUs that went in those old boards had no
multiplier of their own?

where do they get the multipiler number from like 10.5 or 9. A signal
the board? or within the cpu itself.

when i read abou the cpu being locked, it always says "it doesn't
respond to a multiplier change in the BIOS or board" . But it seems to
me that the CPU doesn't just not respond. It multiplies the FSB by some
fixed number. The old CPUs didn't do that, did they?

the multiplier seems to have moved from the board(in the old days) to
the cpu(nowadays)?!

Except for Pentium 4 M (for mobile), all Intel x86 CPUs since the Pentium II
300 (first produced in 1997), have LOCKED clock multipliers that can NOT be
changed. SOME Pentium and Pentium II CPUs prior to the Pentium II 300 are
multiplier LIMITED, some are UNLOCKED, some are LOCKED.

NO jumpers on any motherboard affect the clock multiplier of Intel x86 CPUs
newer than the Pentium II 300.

NO settings in the BIOS affect the clock multiplier of Intel x86 CPUs newer
than the Pentium II 300.

ALL Celeron CPUs are clock multiplier LOCKED.
ALL Pentium III CPUs are clock multiplier LOCKED.
ALL Pentium 4 CPUs are clock multiplier LOCKED.

Even if the BIOS has a clock multiplier setting, changing the setting has NO
effect.

Try the Intel document available at
http://www.intel.com/design/pentiumi...s/24509501.pdf
for information on how the CPU sets the clock multiplier.

Phil Weldon


wrote in message
ups.com...
i see that new CPUs have the multiplier within. But I recall that old
board had a jumper for setting the multiplier. Am I then right in
assuming that the old CPUs that went in those old boards had no
multiplier of their own?

where do they get the multipiler number from like 10.5 or 9. A signal
the board? or within the cpu itself.

when i read abou the cpu being locked, it always says "it doesn't
respond to a multiplier change in the BIOS or board" . But it seems to
me that the CPU doesn't just not respond. It multiplies the FSB by some
fixed number. The old CPUs didn't do that, did they?

the multiplier seems to have moved from the board(in the old days) to
the cpu(nowadays)?!

my interest wasn't really which were locked and which were unlocked.


I found the ans to where the mult is - all quotes are googlable on
usenet or the web.

--
"The multiplier is "inside" the CPU. "
--
"The multiplier is in the processor and is input to a phase locked loop

which multiplies up the FSB clock for the internal processor clock. "
--

and this gerat one from
http://www.computerdoctor.co.uk/FAQs/processors.html

explaining the multiplier and then second paragraph, contrasting with
the fsb

Computer Doctor: There are two factors that control CPU speed, the
speed of the motherboard bus and the internal multiplier in the CPU.
Motherboards may have multiplier settings, but these settings merely
"tell" the CPU what to do, and the CPU is free to ignore those settings
if so designed. Most Intel processors come with the multiplier locked,
so that if you do change the multiplier setting on the motherboard, the
CPU will simply ignore it.

Starting with the Pentium II Intel designed it such that the CPU
"tells" the motherboard what the bus speed (and voltage) should be via
two pins called BSEL0 and BSEL1. Motherboards can however include
override capabilities for these settings, which will ignore what the
CPU says and set the bus speed (or voltage in some cases) to whatever
you want. Unfortunately, Intel's own boards do not allow this type of
"hot rod" control, and you are left stuck with the default settings
dictated by the CPU. ..

---------------

I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.

Try some more research.

Phil Weldon

wrote in message
oups.com...
my interest wasn't really which were locked and which were unlocked.


I found the ans to where the mult is - all quotes are googlable on
usenet or the web.

--
"The multiplier is "inside" the CPU. "
--
"The multiplier is in the processor and is input to a phase locked loop

which multiplies up the FSB clock for the internal processor clock. "
--

and this gerat one from
http://www.computerdoctor.co.uk/FAQs/processors.html

explaining the multiplier and then second paragraph, contrasting with
the fsb

Computer Doctor: There are two factors that control CPU speed, the
speed of the motherboard bus and the internal multiplier in the CPU.
Motherboards may have multiplier settings, but these settings merely
"tell" the CPU what to do, and the CPU is free to ignore those settings
if so designed. Most Intel processors come with the multiplier locked,
so that if you do change the multiplier setting on the motherboard, the
CPU will simply ignore it.

Starting with the Pentium II Intel designed it such that the CPU
"tells" the motherboard what the bus speed (and voltage) should be via
two pins called BSEL0 and BSEL1. Motherboards can however include
override capabilities for these settings, which will ignore what the
CPU says and set the bus speed (or voltage in some cases) to whatever
you want. Unfortunately, Intel's own boards do not allow this type of
"hot rod" control, and you are left stuck with the default settings
dictated by the CPU. ..

---------------

I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.

wrote:

i see that new CPUs have the multiplier within. But I recall that old
board had a jumper for setting the multiplier. Am I then right in
assuming that the old CPUs that went in those old boards had no
multiplier of their own?

where do they get the multipiler number from like 10.5 or 9. A signal
the board? or within the cpu itself.

when i read abou the cpu being locked, it always says "it doesn't
respond to a multiplier change in the BIOS or board" . But it seems to
me that the CPU doesn't just not respond. It multiplies the FSB by some
fixed number. The old CPUs didn't do that, did they?

the multiplier seems to have moved from the board(in the old days) to
the cpu(nowadays)?!


The multiplier is, and always was, 'on the chip'.

A low frequency clock is provided to the CPU which internally multiplies it
up to the needed core frequency. Now, from a practical matter of maximizing
the usable CPUs from the large manufacturing die it's convenient to have
more than one multiplier on the die so the cpus which can run faster can be
clocked faster but the slower ones used as well, albeit at a slower speed
(and for a lower price).

And the easiest way to do that is to have some select lines that pick which
of the available multipliers to use. And it's also easiest to simply
provide pins for them and put jumpers on the motherboard with instructions
on which ones to set where for the particular processor purchased.

This, btw, is how the 1.5x setting on a Pentium Classic becomes a 3.5x on
the Pentium MMX and why Cyrix multipliers often didn't match what the Intel
ones were. What the motherboard 'multiplier' lines select is determined by
the processor. By themselves they have no meaning.


As the manufacturing process improves more and more of the total processors
will run at the faster speeds, but there's still a market for the cheaper,
slower rated, ones. And if enough people will buy the slower ones it's
worth it to simply take some of the faster ones and mark them with the
slower rating. There is also the matter that a slow one may run 'fast'
under some conditions although not all and so don't meet specification.
Like, maybe it works as long as the room temperature is under 80F. Or it'll
work if the power supply runs a tad bit high but not if it's on the low
side of the acceptable range. And, lastly, some of the slow ones may still
be simply slow ones.


Now enter people trying to make a fast buck at the buyer's expense. Buy
slow processors then remark and sell them as the faster ones. They may or
may not work. Of course, the flaky ones get blamed on the processor
manufacturer.

Counter move: Fix the select lines so they cannot be changed. They're
accessible during manufacture and for testing to qualify the processor
speed rating, so you can still use from slow to fast, and then 'burned in',
like a programmable memory, after the rating is selected.

Functionally it's the same. It's just that the external select lines are
intentionally broken to prevent tampering.

wrote:
[...]
"The multiplier is in the processor and is input to a phase locked
loop

which multiplies up the FSB clock for the internal processor clock. "

This one is the correct one, but possibly can be interpreted wrong. What it
means is the following:

FSB --- PLL -------------+--- CPU CLK
^ |
| |
+-- Divider ----+

A PLL can be thought of a a magic thing that adjusts its output so that the
two inputs are the same. The divider is loaded with the "multiplier". So if
you have a 200MHz FSB and a 10x "multiplier" then the PLL will put out 2GHz:
the divider takes the 2GHz, divides it by 10 to give an output of 200MHz,
which matches the other input to the PLL. The divider usually can be
configured for a range of values. This is all inside the CPU.

[...]
I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.

Err, memory multiplier? I think you may be slightly confused here ...

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
Add michael@ to emboss.co.nz ---+--- My inbox is always open

I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.

Err, memory multiplier? I think you may be slightly confused here ...

SDRAM - Is Synchronous with a capital S, so it has a clock. And all
clocked devices in a computer derive their clock from the FSB. And if
they're not running at the speed of the FSB, then they must be using a
multiplier (or dividor). I recall running FSB=100, and SDRAM at
133MHz. then some electronics (a memory multiplier and/or dividor )
was making it run at 4/3 (as in four thirds) times the FSB. The
question, was then whether this thing (which I was calling a ''memory
multiplier'), is inside the memory - just as the CPU multiplier is
inside the CPU. I assumed it was inside, and that the only significant
difference, was that memory clocks are not locked, - they listen to
the speed suggested by the mobo.

wrote:

I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.


Err, memory multiplier? I think you may be slightly confused here ...


SDRAM - Is Synchronous with a capital S, so it has a clock.

True. The system provided memory bus clock.

And all
clocked devices in a computer derive their clock from the FSB. And if
they're not running at the speed of the FSB, then they must be using a
multiplier (or dividor).

True, depending on who 'they' are.

I recall running FSB=100, and SDRAM at
133MHz. then some electronics (a memory multiplier and/or dividor )
was making it run at 4/3 (as in four thirds) times the FSB.

Yes.

The
question, was then whether this thing (which I was calling a ''memory
multiplier'), is inside the memory - just as the CPU multiplier is
inside the CPU.

No

I assumed it was inside,

No.

and that the only significant
difference, was that memory clocks are not locked, - they listen to
the speed suggested by the mobo.


Originally, memory was run at the same speed as the FSB, using the FSB
clock, (which is a lot simpler for the chipset as everything is running in
step with each other) but modern chipsets provide a separate memory clock
that can be different than the FSB.

The memory has no idea of it nor any multiplier. It just runs at the speed
of the memory bus clock.

thanks for that info. I pity the BIOS programmer that includes a drop
down menu where the user 'selects a speed' !
Most speeds probably aren't supported (unless processors have 30
multipliers going from 0 to 15 in 0.5 increments!),. The drop down
menu is misleading - and a misleading GUI is dangerous. And that's just
from the user's perspective.
I imagine that the only reason they don't cause people problems is that
CPUs nowadays are multiplier locked!

Since you already seem quite convinced that you know the answers, why ask
the questions?

All memory currently used in computers have a clock signal to drive memory;
DRAM, DDRAM, DDRAM2, SDRAM, RAM,SRAM, ROM, EROM, EEROM, RDRAM, ferrite core
non-volatile memory, ...

You really should try the Intel website. It might clear up some points that
we can't seem to explain. After all, the three who have posted in reply to
your original question have only posted 10,000 or so messages here.

Phil Weldon






wrote in message
ups.com...
I assume that the memory multiplier is internal to ram , and so the
mobo tels the ram what multiplier to use. Thus far, - it seems to me -
memory is unlocked.

Err, memory multiplier? I think you may be slightly confused here ...

SDRAM - Is Synchronous with a capital S, so it has a clock. And all
clocked devices in a computer derive their clock from the FSB. And if
they're not running at the speed of the FSB, then they must be using a
multiplier (or dividor). I recall running FSB=100, and SDRAM at
133MHz. then some electronics (a memory multiplier and/or dividor )
was making it run at 4/3 (as in four thirds) times the FSB. The
question, was then whether this thing (which I was calling a ''memory
multiplier'), is inside the memory - just as the CPU multiplier is
inside the CPU. I assumed it was inside, and that the only significant
difference, was that memory clocks are not locked, - they listen to
the speed suggested by the mobo.