A couple months ago, we took a look at the low voltage (LV) server CPU market. At the time, we focused on four-way solutions using two dual-core processors, since those represent the largest slice of the server pie. Our conclusion was that while the power savings brought about by using low voltage CPUs were real, processor choice was only one part of the equation. AMD came out ahead overall in performance/watt, not because they were faster or because their CPUs used less power, but rather because their platform as a whole offered competitive performance while using less power.

We discussed previously exactly what's involved in a low voltage part, but of course the picture is far bigger than just talking about power requirements. Take for example Intel's low-voltage Woodcrest parts; they are rated at 40W compared to the regular Woodcrest parts that are rated at 80W. The price premium for upgrading to a low-voltage part varies; in the case of AMD it's typically anywhere from $100 to $300 per CPU, while on the Intel side some low-voltage parts cost more, the same, or even less than the regular parts (i.e., the Xeon 5140 currently sells for about $450 while the low voltage Xeon 5148 only costs $400). Regardless of price, it's difficult to justify low-voltage processors in terms of power bill savings.

An extra 40W of power in a device running 24/7 for an entire year works out to around $35 per year, so at the low-end of the equation you would need a minimum of three years to recoup the investment (at which point it's probably time to upgrade the server). Other factors are usually the driving consideration.

Saving 40W per CPU socket may not save you money directly in terms of power bills, but generally speaking these chips are going into servers that sit in a datacenter. Air conditioning for the datacenter typically has costs directly related to the amount of power being consumed, so every 40W of power you can save could end up saving another 20W-40W of power in air conditioning requirements. That's still not even the primary concern for a lot of companies, though.

Datacenters often run dozens or even hundreds of servers within a single large room, and the real problem is making sure that there's enough power available to run all of the equipment. The cost of building a datacenter is anything but cheap, and if you can pack more processing power into the same amount of space, that is where low-voltage parts can really become useful. Blade servers were specifically created to address this requirement, and if you can reduce the total power use of the servers by 20% that means some companies could choose to run 20% more servers.

Of course, that doesn't mean that every company out there is interested in running a datacenter with hundreds of computers, so individually businesses need to look at what sort of server setup will best fit their needs. After determining that, then they need to look at low-voltage CPUs and decide whether or not they would actually be helpful. Assuming low-voltage parts are desired, the good news is that it's extremely easy to get them in most modern servers. Dell, HP, and other large server vendors usually include low-voltage parts as an easy upgrade for a small price premium. And that brings us to our low-voltage CPU update.

Intel Quad G-Stepping

Intel doesn't seem to sit still these days, pushing the power and performance envelope further and further. Recently, Intel announced two new G-stepping quad-core parts. The new parts run at the extreme ends of the power consumption spectrum. The first is a 2.0GHz 1333FSB part that runs at 50W while the second is a 3.0GHz 1333FSB part that runs at 120W. There are two main changes to the G-stepping parts, the first of which is power consumption: G-stepping introduces optimizations for idle state power. The second change involves enhancements to the Virtualization Extensions (VT), which mainly improve interrupt handling in the virtualization of Microsoft Windows 32-bit operating systems.

Of course, we would be remiss if we didn't mention AMD's recently launched Barcelona processor here. AMD expects their new quad-core processor to run within the same power envelope as the previous dual-core Opterons, which means twice as many CPU cores potentially without increasing power requirements, resulting in a potential doubling of performance/watt on the socket level. Low-voltage (HE) Barcelona parts will still be available, but even the regular chips include many new enhancements to help with power requirements. We are doing our best to get some additional Barcelona servers in-house in order to test this aspect of the performance/power equation and we hope to follow up in the near future.

One final item worth mentioning is that Intel's 45nm Harpertown refresh of Clovertown is due out in the very near future, which is one more item we can to look forward to testing. Unlike the desktop world, however, acquiring and testing server products often requires a lot more time and effort. Even with the appropriate hardware, the sort of benchmarks we run on servers can often take many hours just to complete a single test, and there are many parameters that can be tuned to improve performance. Since there aren't a lot of early adopters in the server market, though, we should be able to provide you with results before any of the IT departments out there are ready to upgrade. Now let's get on to the testing.

Benchmarking Low Voltage
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  • Justin Case - Saturday, September 15, 2007 - link

    Could Anandtech restrict the advertising to the banners? Editorial advertising forces poor ad-blocker programmers to work overtime.

    First, right after the Barcelona (AMD quad-core) launch, we get an article titled "Quad core comes to play"... that pits Intel quad-core CPUs against AMD dual-core ones (published *after* AT covered Barcelona, in Johan's article). Secondly, the article ends with a link to the "Intel resource center". Finally, the article's icon, which contains AMD's logo, links to Intel's site.

  • Proteusza - Saturday, September 15, 2007 - link

    I think Anandtech knows which side of its bread is buttered.
  • Frumious1 - Saturday, September 15, 2007 - link

    You people - and you especially, Mr. Justin Case who LOVES AMD - are pathetic. "It's so unfair - AMD tries so hard and they have their quad core part shipping now and AnandTech intentionally published an article they had worked on for weeks right after the K10 launch in order to slight AMD!" Care for some cheese with your whine?

    I guess I'm one of the few that can read all of the articles here and see what ISN'T explicitly stated? How about this one from Anand's Phenom "performance estimate":


    Then, at the very end (literally two hours before publication) of our benchmarking, the AMD server stopped POSTing. As of now the system will simply sit there and spin its fans without actually putting anything on the screen. A number of things could have happened, but thankfully the Barcelona system decided to die after we ran all of our tests.

    Now let me tell you, as an IT guy that is ABSOLUTELY INSANE! We are talking an enterprise part, and it died during testing. Read the pre-launch articles as well, and you get the impression that AMD is scrambling like crazy to rush this out the door, that they've had all sorts of difficulties, and that at best Barcelona/Phenom need a few more months in the oven before they're fully baked. I can't even imagine any large corporation seriously considering Barcelona with statements like that, at least not until the BIOS revisions and everything else are worked out. But hey, let's let the blind AMD fanboys complain about biased coverage because Anand and company didn't run additional tests on a Barcelona server that broke down during testing!

    You know what would be fair? It would be fair if Anand basically ripped AMD a new one and said what a complete joke the Barcelona launch has been. They got "final" CPUs one week before the launch: "We went from no Barcelona, to fist-fulls of Barcelona in one weekend." Ask any of the tech people out there when they first saw Harpertown CPUs in house. Yes, a product that hasn't been officially unveiled yet, and I'd bet there are thousands of the processors in the hands of testers, businesses, reviewers, etc. But AMD is freaking awesome because they made a new processor.

    AMD having problems isn't the fault of Intel, Anandtech, NVIDIA, or anyone but AMD. They are failing to execute, they are missing windows of opportunity, and all the fanboys can do is try to find any excuse to blame someone other than the real culprits. AMD has issues right now, they are losing money, and it doesn't look like Barcelona is going to do anything beyond maintaining parity at best. Why don't you complain about people not benchmarking with the cherry picked 3.0GHz Barcelona chips that aren't on any roadmaps for the next year while you're at it? Complain about the unfair comparisons where a $350 Barcelona is compared to a $350 Clovertown, because the Intel chip runs at a 20% higher clock speed?

    Again: pathetic. That's all your diehard AMD dedication is. If they had the better processor, that would be great, but it appears that they don't and very likely they won't for a long time. Frankly, I'm not sure they can survive the coming years if they continue their present trend. Hopefully IBM can bail them out (again).
  • Proteusza - Sunday, September 16, 2007 - link

    Its got nothing to do with love for AMD or Intel.

    Had the situation been reverse, I would have said the same thing. The article's title is quad core comes to play. Now, as far as I see it, that can be interpreted in one of two ways:

    1. Intel has just brought out their new quad core cpus so we can finally test them against AMD's dual core cpus.
    2. AMD has just released their quad core cpus, so we can finally test quad core cpus from both manufacturers.

    Now, we know that 1. is false because Intel has had quad core cpus for over a year or something. And we know that 2. is also false because AMD's quad core cpus werent tested in this article.

    So, at the end of the day, we have a meaningless title. Quad core comes to play? Duh its been out for ages.

    In any case, I dont think that Anandtech are biased towards Intel. Oh no, I think they are just paid to do advertising articles sometimes. Like almost all sites. Look at this article: it comes out within days of AMD launching its server quad core cpus, the AMD/Intel logo goes to Intel's site, there is an Intel resource centre link at the end of the article. Too many coincidences for me to think this isnt anything but advertising.

    Again, I will state I enjoy cpus from both manufacturers, and I have no preference. But this is just poorly disguised advertising. Had I known less about cpus, I would have thought the CPUs being tested were Barcelona cpus, and that it was found that Intel were better. You'd be surprised what people pick up from skimming over articles.
  • iceburger - Monday, September 17, 2007 - link

    IMHO the article was not really biased - it only convinced me that intel doesn't have such a great "low power" processor unless the load is kept high through virtualization, because in the real world there aren't that many servers that run at 100% 24/7. It was ok up until the "intel resource link"...and then I found out about the logo.........
    Now how much are THEY paying for each click-$0.25? $0.30?
    Wow...I'm speechless.
    But it fits the bill- intel is the one that pays Google to advertise them when you search AMD. Why would I not think that AT is on someone's payroll? Not a real surprise- following steadily into THG shoes- away from enthusiast site , closer to click generator.
    One step closer to deleting my bookmark.
  • JarredWalton - Tuesday, September 18, 2007 - link

    Despite what you may think, the advertising is totally separate from any editorial content. I have no idea who even advertises with us, and there has never been any suggestion of doing a good review for an advertiser - quite the opposite in fact. I have heard it specifically stated more than once, "Just because [company X] wants us to look at a product doesn't mean we need to do so. If it's interesting, then fine, but we are not an extension of the marketing departments."

    Now, obviously Intel is an advertiser; no surprise there since they advertise with just about every hardware site out there. Do they pay extra for a link that says "Intel Resource Center" at the end? Probably - I don't even know - but that link is automatically inserted by the document engine whenever we (or really I, given I'm the content editor) select Intel as the manufacturer on an article. As for the logo... well, that's tied to the same thing.

    I have now changed the manufacturer to "Various" as opposed to Intel, which makes the logo do... nothing, other than take you back to the main AT page. (I wish we got paid for every click on that....) I didn't really think about it when posting the article, and since it was primarily an update of the Dual-core results only with an Intel Quad-core CPU, I figured it was sensible that Intel was the primary manufacturer and set it accordingly. Thus, the logo took you to the Intel site, just like the logo in my review of the HP Blackbird 002 links back to HP when you click it.

    Sorry for the confusion, but the conspiracy theories are unfounded. Back to your regularly scheduled articles, and feel free to check back tomorrow afternoon for a continuation of this series.

    Take care,
    Jarred Walton
    Senior Editor
  • JarredWalton - Sunday, September 16, 2007 - link

    See above. The actual title is: "Low Power Server CPU Redux: Quad-Core Comes to Play" Note the Low Power part; the Xeon L5335 L5320 and L5310 are indeed newer parts - the L5335 in particular. We looked at LV Xeon and Opteron last time (something like SIX MONTHS after the parts were initially released), so the fact that this article continues from that point as opposed to the latest Barcelona isn't particularly relevant. Different editors, different testing procedures, different locations. Barcelona and Harpertown testing for a future article are in progress... which means not done, which is why this article was posted now without such information. I'd love to get all the latest data for every option out there "yesterday" as well; unfortunately, reality isn't so easy.
  • Justin Case - Saturday, September 15, 2007 - link

    I "love" AMD about as much as I love any other mega corporation (which is to say very, very little). I buy whichever CPUs give better performance per dollar or (in very rare situations) better performance per watt. Right now that means Intel for laptops and 1S workstations, AMD for servers, and either one for midrange desktop systems.

    What I definitely do not love is the way some of the main "hardware review" websites have turned into an extension of the manufacturers' marketing departments, basically publishing press releases, fake "reports" and "editorial" ads. Hardware review sites are supposed to be allies of the consumers, not allies of the industry.

    If it wasn't for Anand's and Johan's articles (and the comments from a small number of smart and informed people), this site wouldn't be worth reading at all, these days.
  • formulav8 - Friday, September 14, 2007 - link

    Just somewhat curious as to why the hybrid AMD/Intel Logo on each page of the review next to the author info has a link that goes to Intels site? Obviously anand can do what he wants, I just saw it as kinda wierd that a hybrid logo with AMD on it would go to Intel? :?

  • steveha - Friday, September 14, 2007 - link

    How about adding Q6600 based 1U server into the mix this takes the good parts of boths systems, Low usage Intel CPU and Low usage DDR yet still gives 4 * 2.4Ghz Cores.

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