Performance Per Watt - Atom rules ok?

[MSIC]

Does anyone have, or can link to a chart of all modern CPUs showing performance per watt?
It's purely for interest, but I was wondering if the Atom really is the best CPU in this regard, or if a Core i5 could give it a run for its money for example.

[arthurleung]

My 2 yrs old C2D T8300 beats Atom hands down for performance/watt.

And depends on what you mean by "Performance".

• Is it general processing?
• Blu-ray decoding?

GPU with integrated h264 decoding will beat any CPU in "performance"/watt.

Many factors affect the performance/watt

• Graphics card that you are going to use (low power for Atom)
• Motherboard (some northbridges use crazy amount of power)
• Overclocking / Undervolting
• Amount of time stay idle

If it is your main computer, you'll likely to keep it on. If it is not, you can switch it off once it finish its job.

For example having an Atom for general browsing, and having an i5 for gaming / video encoding.

My HTPC with an AMD X4 920 is very power efficient. Idle at 49W and peak at 98W. Adding a high end GPU will likely double or triple that figures.

[mikerr]

Atom's design spec was low power and low cost.
Also Atom only really rules in power/performance if you want low total power usage < 10W

Other CPUs like mobile C2D will beat it in power/performance - but their total power usage will be 40W+ and cost much more.

[MSIC]

My 2 yrs old C2D T8300 beats Atom hands down for performance/watt.

Really? Can you give me any evidence? (I'm not talking about total system watts drawn, i'm talking about CPU watts)

And depends on what you mean by "Performance".

No particular measure really, anything at all.

If it is your main computer, you'll likely to keep it on. If it is not, you can switch it off once it finish its job.

There is no computer, this is just a theoretical question.
Thanks anyway for the reply.

Atom's design spec was low power and low cost.

Thats a very good point.

Also Atom only really rules in power/performance if you want low total power usage < 10W

Other CPUs like mobile C2D will beat it in power/performance - but their total power usage will be 40W+ and cost much more.

If you graph power drawn vs performace (by whatever measure you chose), surely any C2D would draw at least 5 times (or more) as much as an atom - so would it be more than 5 times faster?

That's why I was asking about a graph - not to establish if C2D's / Athlons etc are better, since of course they are more powerful, but to ask about performace relative to wattage.

[TooNice]

This is the best I've found: http://www.tomshardware.com/reviews/...-330,2141.html
It's pretty hard to benchmark system without a system, so the power draw are measured for the entire system. Still, I am reasonably convinced that the Core2 is more efficient than the Atom.

[arthurleung]

http://www.xtremesystems.org/forums/...d.php?t=188609

Atom 1.33Ghz Z520 has a score of 1159, translating to my N270 on my DELL Mini 9 would be about 1394
The U7600 has a score of 2832, my C2D T8300 is twice the clockspeed so would be ~ 5664, which is exactly 4 times the CPU score of the Atom @ 1.6Ghz.

My Atom draws between 10~15W from the socket (using power meter) depending mainly on screen brightness. My DELL notebook draws 20W from the socket idle, 39W at full load. Note that my CPU is undervolted from stock (1.1375V to 1.025V). On battery power, screen off, wireless off and idling can go down to 7.4W, which my 9-cell battery shows remaining battery as 11 hours (This is how I use it in lecture)

My comparison is somewhat bias, as my Mini 9 had the more power hungry variant of the 945 chipset. The newer chipsets might have a lower power usage. I'm looking at overall system power draw.

By the way, that Atom lagged like hell when Hexus had those fancy Flash in the forum.

I think if you go for say, a mobile i7-720QM you get even more P/W. It depends on if you need to go to such extreme for the P/W rating.