Underclocking..

On Jan 31, 7:42 pm, Robert Baer <robertb...@localnet.com> wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Tue, 31 Jan 2012 09:00:31 +0000, Martin Brown
|||newspam...@nezumi.demon.co.uk> wrote:
Robert Baer wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Sun, 29 Jan 2012 17:54:17 -0800, Robert Baer <robertb...@localnet.com
wrote:
..already looked at the various references the baby bird (GooGull)
proffered to no avail regarding the following:
Are there any _disadvantages_ other than speed?
What are you underclocking? How much? Most high-end microprocessors
use some
sort of dynamic logic so there is a lower limit to the clock speed.
Purely
static processors (most UCs) can be run down to DC, so there isn't any
problem
there. Depending on the I/O, there may be real limitations there, too,
particularly if timing loops are used or the clock is used for other
things.
The only other problem I can see is that, they won't heat the room.
Specifically, a Pentium 2-266 clocked down to 180.
A P-II will have dynamic logic so you can't go all the way to DC but I'd bet
180MHz would work, as long as the multipliers are there. Intel did quite a
bit of clock-locking back then.
Why would you bother?
They are a waste of space and better off clocked at 0Hz.
Indeed. There are far better low-power solutions today. The P-II was a pig.
I am not looking for low power; i need a computer with at least one
ISA slot, and it would be nice to have the hardware speaker driver
available.
That last part is a dig to the idiots that designed the Compaq
Presario 5185 and similar (NO speaker circuitry).
*
The only reason for the underclocking is that the slot one CPU got
hot as all heck without a fan at its rated 200MHz clock.
So now a fan and clock at 180MHz which the motherboard allows.

I have a similar problem with an IBM "think center" job, nice and
compact, I note good effort on the part of IBM engineers to control
thermodynamics, but I'm uncertain it's sufficient.
The upshot is I have an intermittent fault in it. If I set it outside,
in
cold then bring it in it'll run beauts for a couple of days then die.
I went to BIOS and it allows some CPU clocking reduction, the
unit is very nice but I perfer reliability to top performance so I'll
take the performance hit.
I intend to replace the enclosure with heavy 1/4" screen in place of
sheet metal to improve ventilation cooling.

If I can solve the intermittent fault I'll post.
Ken






I add fans, front and back of a tower case which helps a lot.

On Feb 1, 3:42 am, Robert Baer <robertb...@localnet.com> wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Tue, 31 Jan 2012 09:00:31 +0000, Martin Brown
|||newspam...@nezumi.demon.co.uk> wrote:
Robert Baer wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Sun, 29 Jan 2012 17:54:17 -0800, Robert Baer <robertb...@localnet.com
wrote:
..already looked at the various references the baby bird (GooGull)
proffered to no avail regarding the following:
Are there any _disadvantages_ other than speed?
What are you underclocking? How much? Most high-end microprocessors
use some
sort of dynamic logic so there is a lower limit to the clock speed.
Purely
static processors (most UCs) can be run down to DC, so there isn't any
problem
there. Depending on the I/O, there may be real limitations there, too,
particularly if timing loops are used or the clock is used for other
things.
The only other problem I can see is that, they won't heat the room.
Specifically, a Pentium 2-266 clocked down to 180.
A P-II will have dynamic logic so you can't go all the way to DC but I'd bet
180MHz would work, as long as the multipliers are there. Intel did quite a
bit of clock-locking back then.
Why would you bother?
They are a waste of space and better off clocked at 0Hz.
Indeed. There are far better low-power solutions today. The P-II was a pig.
I am not looking for low power; i need a computer with at least one
ISA slot, and it would be nice to have the hardware speaker driver
available.
That last part is a dig to the idiots that designed the Compaq
Presario 5185 and similar (NO speaker circuitry).
*
The only reason for the underclocking is that the slot one CPU got
hot as all heck without a fan at its rated 200MHz clock.
So now a fan and clock at 180MHz which the motherboard allows.

There were cpu-fanless P2s too, they just had a much larger heatsink
on the cpu. ISA slots were moderately common on P3s too, with just 1
or sometimes 2 such slots on the mobo. And a P3 is surely a better
proposition, if you only need one ISA slot.


NT
Yes, this CPU had the large heatsink - but got hot a i indicated.