AMD Beats Intel in Power-Efficiency Study

Ted Samson writes "AMD Opteron servers proved up to 15.2 percent more energy-efficient than those running Intel Xeon in a server-power-efficiency test performed by Neal Nelson and Associates, InfoWorld reports. That translates to annual electricity savings between $20.29 per server and $36.04 per server, depending on the workload, the study concluded. The benchmark tests were conducted on similarly configured 3GHz systems running Novell SUSE Linux, Apache2, and MySQL."

Comments

Re:Sponsorship?

[florescent_beige]

If you read the 6th paragraph of the article, AMD wasn't aware of this test, according to "John Fruehe, manager of worldwide market development for server/workstation products at AMD"

Re:Different Power Supplies

[segedunum]

If you read the PDF, you'll see that the AMD system was tested with a 500W power supply while the Intel one was tested with a 600W one. I wonder how much of the different can be associated with that.

None. They would draw exactly the same power whether they used 500W or 600W PSUs. Besides (and I haven't got all the way through the article), they may just be using recommended PSUs in pre-built machines.

Re:Different Power Supplies

[Gabrill]

however differing power supplies do have different efficiencies of conversion. So we're really comparing top-to bottom solutions, and the processor may actually be a small part of the energy savings.

Re:Different Power Supplies

[Anonymous Coward]

Actually the power capacity of a supply WILL affect the power measured as even same amount of power output will be on different part of the efficiency curves even if component losses are identical. Power supplies tends to be most efficient from 1/3 to 2/3 of their power ratings.

For a more scientific study, they should use the same power supply.

Re:Different Power Supplies

[florescent_beige]

IANAEE but I found this thing (pdf) from DELL that has a "typical" efficiency curve (fig A, on the third page of the pdf, page # 64) that shows efficiency is pretty flat from 35% up to max load. Within maybe 5%.

Re:3.0Ghz May Not Meen Equal Performance

[RootWind]

Anandtech recently did that kind of power efficiency vs. performance test actually: (2.6Ghz vs. 2.33ghz), with AMD coming out on top: http://www.anandtech.com/IT/showdoc.aspx?i=3039

Intel CPU is only 1 part that uses a lot of power

[mauriceh]

We see similar when we build systems.
The Intel CPUs are competitive with the Opterons on power consumption.
But: The whole system uses more with Intel.

Why? the northbridge memory controller is a separate chip with Intel, and it is very power hungry.
In the AMD chips the memory controller is a part of the CPU.
In the case of a similar dual XEON compared to a dual Opteron,
the XEON machine uses about 80W more power.

What a lot of these studies do not even get into is cooling cost.
for every watt of power , which ends up heat, we have to expend at least 1.5 watts, on air conditioning.

As for the comment about the size of the power supplies, that is irrelevant.
The maximum rated output of a supply has nothing to do with the power consumed.

Bottom line:
Assuming an Intel XEON server uses about 80 watts more than an equivalent AMD one,
which is what we see when we build them:
80w x 24 hours/day x 365 days is 700KWh. @ 9c/kWh costs $63/year.
Add aircon costs for that extra 80W:
120w x 24 hours/day x 365 days is 1050KWh. @ 9c/kWh costs $96/year.

Therefore, a machine using an extra 80W costs an extra $160 to run in an air conditioned room.

Source of power rates:
http://www.neo.ne.gov/statshtml/115.htm

Re:Different Power Supplies

[kaiwai]

I'd like to know why they compared a Woodcrest Xeon, circa June 2006 to the latest and greatest Opteron of today.

Re:3.0Ghz May Not Meen Equal Performance

[Iam9376]

I just want you to know...

That Page is over 4 years old..

*sigh*

Re:Intel CPU is only 1 part that uses a lot of pow

[darthflo]

Most of this does sound pretty logical to me, however you make one point I don't understand at all...

for every watt of power , which ends up heat, we have to expend at least 1.5 watts, on air conditioning.

To my (somewhat limited) knowledge, an Airconditioner should cool about three to four times as much energy as it uses up (Wikipedia says a SEER-13 aircon (which is the minimum level for newly installed air conditioners in the U.S.) ought to pump "3.43 units of heat energy [...] per unit of work energy".). Even if this isn't the case and it'd only pump twice the heat energy it uses up, that would still be a $64 difference to your calculations.
Did I get something wrong or just calculate with horribly over-efficient air conditioning?