Skybuck said:
I am also quite annoyed with AMD and their X2 processor.
The multiplier is locked as some of you know... so properly
underclocking is not possible.
The motherboard had two nice features:
CPU Clock Multiplier or something like that.
and
HT Multiplier.... (hyper transport)
First I tried HT... later I figured it was the wrong setting.
I didnt notice any performance degradation with HT running at 1x instead
of auto/5x ?
Maybe HT is for core to core communication... but I think it's main roll
was memory speed/bandwidth.
Didnt notice a thing... quite odd.
The HT multiplier was unlocked according to CPU-Z
Unfortunately the CPU multiplier not
setting it to 5x or 4.5x or
something instead of 10x had no effect
I am not going to mess with voltages cause I dont know how to do that
properly... and certainly don't want to risk damage
Just gonna wait for the night too cool down before I continue my gaming
Or maybe I do a low power game
Bye,
Skybuck.
With Cool N' Quiet enabled, you can change the CPU multiplier.
If you entered the Windows control panel "Power", if you select the wrong schema,
it can leave the CPU running at full speed. Selecting a different schema,
gives Cool N' Quiet voltage and multiplier changes automatically. This
does not change the peak heat output, but improves thermal behavior
at idle. If you run Prime95, it will get just as hot.
If you use RMClock, you should be able to see the multiplier options.
If no options are visible (as in this picture), check your BIOS settings.
http://1.bp.blogspot.com/_pEfSMUbljUA/SpL8iTa_d7I/AAAAAAAAACY/Kj3D5Qj4L-U/s1600/t2400_rmclock.jpg
You can get RMClock here.
http://cpu.rightmark.org/download.shtml
With a little work, I expect you can create an RMClock schema, that
prevents the top multiplier from being used. And then, even running
Prime95, the temperature could be reduced. But you're not going to
like the reduced CPU performance.
AMD used to have a spec, where for each processor it showed the P-states.
That would explain the minimum and maximum multipliers used, when the
processor was tested at the factory. Most other listings you can find,
only list the maximum multiplier (for top CPU speed).
As an example, I can use a cpu-world.com entry. A 3800+ has a 2GHz CPU
internal clock, and a 200MHz base clock, for a peak multiplier of 10X.
http://www.cpu-world.com/CPUs/K8/AMD-Athlon 64 X2 3800+ - ADA3800DAA5CD (ADA3800CDBOX).html
"In the minimum performance state (P-state) the processor runs at
1000 MHz and 1.1 Volt core voltage. Thermal Design Power in the
minimum P-state is 40.1 Watt"
That suggests the minimum CPU multiplier is 5X. And Cool N' Quiet
can vary the multiplier from 10X to 5X, while Windows is running.
The RMClock dialog box would show six rows of info, for the
allowed multiplier values.
*******
The HT multiplier, sets the clock for the Hypertransport bus. That
is the bus between the CPU and Northbridge. Setting the multiplier
to 1X instead of 5X, reduces bandwidth to your video card by a
factor of five or so. There is a second Hypertransport bus segment,
between the Northbridge and Southbridge. And you can fool around
with that if you want, as well.
The HT multiplier doesn't affect memory, since the memory controllers
are right on the CPU itself. Only the chipset bus bandwidth is affected
by HT.
A legitimate reason for reducing HT multiplier, is if you are
overclocking by raising the base clock on the CPU. If you raise the
base clock from 200MHz to 250MHz, you drop the HT multiplier from 5X
to 4X. Keeping a constant 1000MHz clock on the HT bus. That's the
basic idea. Hypertransport transfer rates, differ from one socket
to another, so my values listed here, are just to illustrate the
concept of staying below the limit for the bus. Some later AMD processors,
use a faster HT bus.
Paul
