Selecting an Appropriate Server CPU

For many businesses, performance isn't the top priority when it comes to selecting a server; chances are that low power and CAPEX budget are higher on the list. AMD's newest Opteron 4100 series is targetting exactly those businesses. The 4100 is the little brother of the Opteron "Magny-Cours" 6100. The Opteron 6100 crams up to two hex-core or quad-core chips in one package. In contrast, the "Lisbon" Opteron package contains only one chip. The "Lisbon" Opteron with C32 socket thus comes with the same improvements that the Opteron 6100 had over the hex-core "Istanbul":

  • Support for DDR3 memory (low voltage also supported)
  • Higher HyperTransport speeds.
  • Improved C1E sleep state.

The dual socket capable Opteron 4100 tries to find a place between the relatively cheap but single socket Xeon 3500/3600 series and the more expensive dual socket Xeon 5600 series. We chose three AMD Opterons and two Intel Xeons for a closer look.

The hex-core Opteron 4162 EE promises to consume no more than 32W (35W TDP), or an amazing low ~5W per core. The chip runs at a modest 1.7GHz and comes with an affordable $316 price tag. You can get a slightly faster 1.8GHz version, the 4164 EE, but that chip costs more than twice as much ($698). As we are searching for low power and inexpensive CPUs, it didn't make the cut. The only disadvantage other than the lower clock speed is the lower clocked HT3 link at 2GT/s instead of 6.4GT/s.

If that is still too expensive for you, AMD has also a quad-core 2.2GHz Opteron 4122 at probably the lowest price ever for a dual socket server CPU: $99. The CPU needs 75W on average according to AMD (95W TDP). You'll probably want to pay a little more for the 2.6GHz 4130 ($125), but unfortunately we didn't get that CPU in our labs. Adding about 15-18% to the performance numbers of the 4122 should tell you what the 4130 is capable of.

Most of you are probably looking for a good balance between power, throughput, single threaded performance, and price. The hex-core 2.1GHz Opteron 4170 HE is a good candidate at only $174. AMD promises that average power should be around 50W under load, with a maximum of 65W.

Simply stated, Intel does not like to play in those price ranges. The cheapest Xeon is priced at $188, and offers you the four cores of the E5603. At 1.6GHz, without Hyper-Threading, and with the L3 cut in half (4MB) we doubt that it will be a good alternative. It also needs a bit more power: 80W.

The only "decent" Xeon in the low price ranges is the Xeon E5606 (four "Westmere" cores at 2.13GHz, 8MB L3, no HT). Unfortunately, we didn't have this chip in the lab. To give you an idea where it would land, we added a Xeon E5506 at 2.13GHz, which is based on the older "Gainestown/Nehalem" architecture and has less L3 (4MB). Based on our past experiences you should add about 10 to 20% of performance to get an idea where the E5606 would land. In general, the Opterons will need to surpass this older chip to be compelling.

The low power Intel chips are priced a bit higher. We asked Intel, and the "slowest" low power chip they would send is the Xeon L5630. It offers four cores with Hyper-Threading (eight threads) at 2.13GHz, 12MB of L3, and consumes a very low 40W TDP. It will need to beat all the Opterons with a decent margin to justify the rather heavy $550 price tag.

In summary, it looks like AMD might have found a some unclaimed territory here as Intel does not offer low power and cheap Xeons. The question of course is whether the performance/watt/price ratio is interesting enough, and that's what we're here to find out.

Server Benchmark Configurations
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  • qrazi - Friday, March 4, 2011 - link

    Don't forget that a higher TDP also requires a higher capacity cooling and PSU, which in turn also means higher power requirements.

    And if it's not the only server in the rack, thermal output can be a real issue.
  • 7Enigma - Friday, March 4, 2011 - link

    Exactly. This point is missed in almost all articles related to power consumption. "But it's only 5 cents per week more...blah....blah....blah".

    Yes but the problem is the cost associated with the REMOVAL of that heat that is often much more expensive and troublesome than the actual moderate increase in power consumption. This is compounded in a server environment where even a slight increase can start to cause issues with air handlers, total power draw for the room, and that extra 5 cents can become a significant increase in operating costs.

    So please before someone else writes a post in this or an upcoming article think the whole situation through. It's not just the additional power the server uses, but what do you do with that extra power (in the form of heat) that really matters.
  • ZL1Corvette - Friday, March 4, 2011 - link

    PSU: I understand that when custom building a server you'll get to match you exact load to your PSU. How about when you're buying a premade though. I don't buy servers but I bet Dell charges a fine premium when you upgrade to the higher dollar CPU. Quick trip to Dell page says the 4170HE is a $102 premium over the 4122. That price makes it look like they keep the same PSU installed. Going with a 4162EE costs $252, which still looks like they're keeping the same PSU. The 35W chip saves you $52 a year. 5 year pay back until you consider heat removal.

    Heat: CPU's make heat through electrical resistance, which is actually a pretty inefficient way to make heat. Your AC system is better, but we'll assume it's equal. You can take all of my original pay back numbers and cut them in half. That means almost all of these chips take from 1.5 to 2.5 years to pay for themselves.

    How long do you keep a server? I'm sure I have no idea, but most companies don't implement a cost saving unless it pays back in under two years.

    You're right, there are extra costs, some of the time. What about the quarter of the year when it's cold outside? How about when you already have the system and are considering upgrading just for the lower operating costs? Too many times I've seen forum posts about people "saving" all this money by reducing their computer power draw by a few watts.
  • JohanAnandtech - Saturday, March 5, 2011 - link

    Quite a few people have given you already a good answer. Check also the "Power cost" by ERJ post out. Most people collocating will pay a fixed cost, and will pay a lot more if they create "bursty power" (i.e. demand more power than was agreed). So requiring a half Amp less or more than your limit can make a big difference.
  • bwj - Friday, March 4, 2011 - link

    Why do you think least power consumption is important for cloud providers? A cloud provider wants to keep all servers running at peak utilization, all day, every day of the week. The platform is at 80% of its peak power consumption when 10% loaded, so there's little cost going from 10% to 100% load. A cloud provider wants the highest throughput per watt at 100% load.
  • duploxxx - Friday, March 4, 2011 - link

    Why would you choose in this configurations for a balanced power schema? doesn't make sense to me and it is very OEM depending weather those power schema work well or not, certainly on Vmware.

    Next time select also LP dimm's although retail might show a price difference, it's no longer the case when you have a decent price reduction from server volume.

    vAPU 2 is a great benchtool but the score i still a bit flawed because of the WEB bench results. You miss a 9th or 10th that would serve files orso.
  • silverblue - Friday, March 4, 2011 - link

    HAHA McAfee makes things more secure?

    Thank you for brightening up my Friday.
  • tech6 - Friday, March 4, 2011 - link

    A test of Watts per unit of work done would have interesting.
  • duploxxx - Friday, March 4, 2011 - link

    People like you should be banned from the internet, your personal feelings towards a certain vendor clearly affect your way of working with IT.

    I pity those who would do any business with you with such a narrow mind. By folks like you we would still be living in the Netburst ERA, wasting hours of time waiting for a job to finish.

    Just FYI in the 2p server compare here there is not a single RAS feature intel has more then AMD, and using the platform you obviously refer too (EX) in a power consumption compare would be a really big joke, just like the more secure intel cpu thx to mcafee hence they just bought the company not let alone integrating this before 2013.....

    Bugs, yeah right, you mean bugs from the one behind the keyboard. we use 1000's of Intel and AMD servers in Hospital environments, both do there jobs more then well.

    Intel is not a standard, x86 is which is btw not created by Intel, not to mention the 64bit you are probably running these days :D
  • duploxxx - Friday, March 4, 2011 - link

    are you really that stupid? we are talking here about server platform. Intel 55xx and 56xx series are connected through Tylersburg chipset, perhaps start reading a bit more.

    thx for the information sharing but I have a feeling that there will be many other people with more added value posts ....
    Your smooth, lightning fast ATOM system seems to be handling the CUT/PASTE typing really well ......

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