Re: [PATCH] Add p4-clockmod driver in x86-64

[Paulo Marques <pmarques@grupopie.com>]

Lee Revell wrote:
> On Wed, 2004-10-27 at 15:59 +0100, Paulo Marques wrote:
> 
>>I am one of the members of the robotic soccer team from the University 
>>of Oporto, and a couple of months ago we were looking for new 
>>motherboards for our robots, because we are starting to need new 
>>hardware (on-board lan, usb2.0, etc.).
>>
>>We really don't need excepcional performance, but we really, really need 
>>low power consumption, so lowering the clock on a standard mainboard 
>>seemed to be the best cost/performance scenario.
>>
>>Could this driver be used to keep a standard p4 processor at say 25% 
>>clock speed at all times?
>>
> 
> 
> Why don't you try the VIA EPIA mini-ITX boards?  These are designed for
> low power applications like yours.  I am running the M-6000 which has a
> fanless 600Mhz C3 processor, the newer fanless models run at 1Ghz.  And,
> on top of that they support speed scaling so you can slow it down even
> more.

Yes, we tried those, but floating point calculations completely kill the 
performance on those boards.

Even at 25% speed a P4 2.8GHz gives a 700MHz clock which completely 
toasts a 600MHz (or even a 1GHz) C3 in floating point calculations... :(

Even more, I can get a Asus mainboard with integrated VGA, LAN, USB, 
Audio, for half the price of a VIA EPIA mini-ITX with comparable integer 
performance. As we always have to buy these things in quantities of 5, 
this can make some difference.

-- 
Paulo Marques - www.grupopie.com

All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke (1729 - 1797)