AMD to allow per-core overclocking for Phenom?

[YKhan]

AMD to allow per-core overclocking for Phenom? - The Tech Report
"There will be a twist, though: a screenshot posted by the site
suggests the new Overdrive will enable discrete overclocking for each
of a Phenom X4 processor's four cores. In the screenshot, a chip is
running with multipliers of 11X, 12X, 12.5X, and 11.5X for its four
cores, achieving respective speeds of 2.93GHz, 3.2GHz, 3.33GHz, and
3.07GHz."
http://techreport.com/discussions.x/13511

 

[nobody]

AMD to allow per-core overclocking for Phenom? - The Tech Report
"There will be a twist, though: a screenshot posted by the site
suggests the new Overdrive will enable discrete overclocking for each
of a Phenom X4 processor's four cores. In the screenshot, a chip is
running with multipliers of 11X, 12X, 12.5X, and 11.5X for its four
cores, achieving respective speeds of 2.93GHz, 3.2GHz, 3.33GHz, and
3.07GHz."
http://techreport.com/discussions.x/13511

What would be the L3 speed then? I'm assuming it runs at full CPU
clock under normal conditions, but if the cores run each at its own
clock speed, there would be no such thing as "CPU clock", unless we
take the average. I'm afraid the average is not much more meaningful
than average patient temperature in a hospital - go average infectious
ward with the morgue, and the result may just be close to the norm
Does it synchronize then to the fastest, or the slowest, or just runs
at stock speed? Can it run asynchronously from the cores? If yes,
wouldn't there be a performance hit that takes away all the advantages
of overclocking each core to its limits and then some? Too many
questions, and not that much in terms of possible advantages.
All this is aside from the usual official stance of chip makers that
does not condone running the chip outside of the spec - unless there
was a change of heart that I didn't notice.
As for the photo...well, Photoshop can produce amazing results in
skilled hands.

NNN

 

[Yousuf Khan]

What would be the L3 speed then? I'm assuming it runs at full CPU
clock under normal conditions, but if the cores run each at its own
clock speed, there would be no such thing as "CPU clock", unless we
take the average. I'm afraid the average is not much more meaningful
than average patient temperature in a hospital - go average infectious
ward with the morgue, and the result may just be close to the norm
Does it synchronize then to the fastest, or the slowest, or just runs
at stock speed? Can it run asynchronously from the cores? If yes,
wouldn't there be a performance hit that takes away all the advantages
of overclocking each core to its limits and then some? Too many
questions, and not that much in terms of possible advantages.
All this is aside from the usual official stance of chip makers that
does not condone running the chip outside of the spec - unless there
was a change of heart that I didn't notice.
As for the photo...well, Photoshop can produce amazing results in
skilled hands.

As I understand it, the L3 cache runs at the external clock speed, not
at any of the internal core speeds.

Yousuf Khan

 

[krw]

What would be the L3 speed then? I'm assuming it runs at full CPU
clock under normal conditions,

As Yousuf said, L3s generally run at the memory interface speed. The
L3 (or at least its controller) generally is part of the memory
interface/BIU.

but if the cores run each at its own
clock speed, there would be no such thing as "CPU clock", unless we
take the average. I'm afraid the average is not much more meaningful
than average patient temperature in a hospital - go average infectious
ward with the morgue, and the result may just be close to the norm

Well, if one CPU is dead... I guess you have a point. ;-)

Does it synchronize then to the fastest, or the slowest, or just runs
at stock speed? Can it run asynchronously from the cores? If yes,
wouldn't there be a performance hit that takes away all the advantages
of overclocking each core to its limits and then some? Too many
questions, and not that much in terms of possible advantages.

L3s are generally large with only two or four ports, usually time
multiplexed, running at the I/O or memory speed.

All this is aside from the usual official stance of chip makers that
does not condone running the chip outside of the spec - unless there
was a change of heart that I didn't notice.

As long as the manufacturer does it, it's not "over clocking". ;-)
This allows them to run each core at its maximum, rather than that of
the slowest.

As for the photo...well, Photoshop can produce amazing results in
skilled hands.

Marketeering is no different. They're just featuring a liability.
;-)

 

[Rick Jones]

As long as the manufacturer does it, it's not "over clocking". ;-)
This allows them to run each core at its maximum, rather than that
of the slowest.

I'm sure the CPU schedulers would _love_ that

rick jones

 

[krw]

I'm sure the CPU schedulers would _love_ that

Why would they care? They'd *BETTER* not assume any timing
relationship.

 

[Bill Davidsen]

AMD to allow per-core overclocking for Phenom? - The Tech Report
"There will be a twist, though: a screenshot posted by the site
suggests the new Overdrive will enable discrete overclocking for each
of a Phenom X4 processor's four cores. In the screenshot, a chip is
running with multipliers of 11X, 12X, 12.5X, and 11.5X for its four
cores, achieving respective speeds of 2.93GHz, 3.2GHz, 3.33GHz, and
3.07GHz."
http://techreport.com/discussions.x/13511

Not really new, Intel Core2 allows the cores to run at different speeds
AFAIK, the /proc/cupinfo shows varying speeds under light load, moving
all to full speed under heavy load.

The newest Intel CPUs, Penryn tech, seem to have the ability to o/c a
single core under light load, on the theory that overall power use will
stay within design limits, and single thread performance will be better.
Since I've only seen this mentioned for the "extreme" CPU, I can't guess
if it will also be on something the average person might buy.