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However, miles are miles, and gallons are gallons. There's no one simple way to measure processor performance

Cars are just as easy and just as hard to compare. For example, how do you compare a Viper's performance versus a Metro's? They explicitely picked miles per gallon, and the Metro is going to win that. Had they instead picked acceleration, the Metro looses. Do the same for processors then. Pick a test and use it. Define strict conditions and go by them. For example, you would get miles per gallon by driving, say 60 MPH down an empty highway with cruise control, not by just telling both drivers to meet you at the gas station and then checking the gas tanks when they get there. So, for the processor, pick a particular benchmark test, say CrystalMark (which, btw, does a nice blend of tests rather than just one -- here's a Google translation version: CrystalMark someone might want to cache that, it's kind of slow even before I post a link on Slashdot) and compare the chips while checking power usage. You don't have to make it needlessly complicated. If one test isn't good enough, use more than one test tool and come up with a rating system that blends the results appropriately. No need to make excuses...

and under Windows, I'm quite happy with crystalcpuid http://crystalmark.info/?lang=en

It also happened that my athlon64 3000+ is still stable when going under the default lowest consumption state (1GHz at 1.1V). It works fine at 800MHz and 0.8V

a nice guide here: http://www.silentpcreview.com/article231-page1.htm l

I've been undervolting my HP zv5000z Athlon 64 notebook since July of 2004, and I got the idea from Silent PC Review where people were undervolting desktop Athlon 64s. I switched to using CrystalCPUID to manage speed and voltage since that initial post was written and most people have switched to RMclock. Lots of people on R3000 Forums and the HP forum at NotebookReview.com have been undervolting their notebooks. I believe I was the instigator on both of those forums.

Anyhow, I'm still undervolting, now with a Mobile-class Athlon 64 3200+ CPU that I swapped in some time ago (HP only used DTR-class chips). AMD is very conservative with their default voltage levels so there's lots of room to work with. I've set my CPU to run at roughly Low Voltage-class levels, close to what a Turion ML is rated to do. The machine is solid. I got great battery life before and even better battery life now. I was able to play DVD video for 3 hours (12 cell battery) and get closer to 4 hours in general use. That's with a 7200RPM HD too. Not bad for a desktop-replacement behemoth.

Note that if your machine usually runs at AMD's 800MHz idle speed, undervolting won't buy you much (if anything). AMD's PowerNOW! is already extremely efficient in normal use. If it jumps to full speed a lot, undervolting does wonders.

So, there's no need to suffer with a 32-bit-only Intel CPU and their awful integrated GPU if you want a long-lasting notebook.

(Anyone know how to undervolt under Linux? That's the one thing I've been missing...)

Use CrystalCPUID covers HP zv5000/zv6000 and Compaq R3000/R4000 notebooks.

Use CrystalCPUID covers HP zv5000/zv6000 and Compaq R3000/R4000 notebooks.

Use CrystalCPUID to manage your AMD64 CPU's speed and voltage rather than the default Cool 'n Quiet power management (set your Power Scheme to "Always On" to disable that, definitely leave the CnQ driver installed). On most HP AMD64 notebooks we've found that you can usually safely set the core voltage at about 0.2V below stock at full speed. Judging by the AMD Thermal Design Guide, that's enough to cut power consumption nearly in half. I swapped in a Mobile-class Athlon 64 3200+ into my Pavillion zv5000z in place of the stock DTR-class chip and have been running 1GHz at 0.8V, 1.6GHz at 1.025V, and 2GHz at 1.225V for months. That puts the full speed power consumption at slightly above AMD Turion ML levels. For the stock DTR chips, 1.3V at full speed is popular.

Of course, in average use, the standard AMD Cool 'n Quiet behavior of running 800MHz at 0.95V while idle will give you battery life that's almost as good as an undervolted setup. 3-4 hours of battery life with a 12 cell battery is common, versus a fraction of that for the poor bastards who bought the P4-based zv5000 series (HP wisely dropped Intel CPUs from their zv6000 line). Undervolting does wonders under heavy CPU load though.

MobileMeter is my favorite way to monitor CPU speed and temperature, and Hot CPU Tester Pro verifies that I didn't go too far.

At least I think so. http://crystalmark.info/CrystalMark/09/ranking.php
Compare your CrystalMark results with those. You can also selectively search for RAMDISK users and ask them... well maybe.

P.S. Cow_ard - that's somethying like Cow_boy, right?