New Xeons bring dramatically lower idle power

Intel’s Xeons have taken quite a bit of market share from AMD’s Opterons in the past year or so, and rightly so, thanks to a nice combination of performance and power efficiency under load. Those Xeons have had a notable Achilles’ heel, though, in the form of high power consumption at idle. (You can see our numbers from when we measured it, for instance.) The Xeons’ high idle power primarily comes from two culprits: the Xeon platform’s use of FB-DIMMs and the CPU chips themselves. This fact has left something of an opening for the Opteron, whose place in the data center has been cemented by its overall power efficiency. However, Intel has just announced some changes to its Xeon lineup today that could change the picture dramatically.

The headline news you may see around the web is the official introduction of two new Xeon models, the X5365 and L5335. The quad-core Xeon X5365 runs at 3.0GHz on a 1333MHz front-side bus, and we reviewed it a while back as part of Intel’s “V8” media creation platform. This CPU has been shipping exclusively in Mac workstations for some time, but should now be more widely available. The L5335 is a new low-power quad-core processor with a 2GHz clock speed, 1333MHz bus, and a thermal design power (TDP) of just 50W—a product distinctly poised to take on AMD’s upcoming Barcelona-based Opteron chips.

The bigger news that you may hear less about is the advent of the new G stepping of chips across the Xeon lineup. These chips are still manufactured using a 65nm fabrication process, but a combination of changes—including the ability to reach lower CPU multipliers and thus lower clock speeds—leads to much lower power consumption at idle for many Xeon models. Here are the numbers Intel presented to us on the reduction in idle power use for its quad-core Xeons:

Clock speed Front-side bus TDP

Old idle power

New idle power

Xeon X5365
3.00GHz 1333 MHz 120W

50W

25W

Xeon X5355
2.66GHz 1333 MHz 120W

50W

25W

Xeon E5340
2.33GHz 1333 MHz 80W

30W

25W

Xeon E5330
2.00GHz 1333 MHz 80W

34W

34W

Xeon E5320
1.86GHz 1066 MHz 80W

30W

30W

Xeon E5310
1.60GHz 1066 MHz 80W

34W

34W

Xeon L5335
2.00GHz 1333 MHz 50W

N/A

24W

Xeon L5320
1.86GHz 1066 MHz 50W

24W

24W

Xeon L5310
1.60GHz 1066 MHz 50W

24W

24W

And for the dual-core Xeons:

Clock speed Front-side bus TDP

Old idle power

New idle power

Xeon 5160
3.00GHz 1333 MHz 65W

N/A

8W

Xeon 5150
2.66GHz 1333 MHz 65W

24W

8W

Xeon 5140
2.33GHz 1333 MHz 65W

24W

8W

Xeon 5130
2.00GHz 1333 MHz 65W

27W

27W

Xeon 5120
1.86GHz 1066 MHz 65W

24W

12W

Xeon 5110
1.60GHz 1066 MHz 65W

15W

6W

Power use at idle drops by as much as 25W per processor—or 50W total in a dual-socket system—for the high-end quad-core Xeons, with smaller reductions for slower CPUs. These improvements may not entirely make up the idle power gap with the Opteron, but they should come fairly close. Given that Intel has the performance lead and double the density of cores per socket, well, let’s just say AMD needs to deliver Barcelona now more than ever.

Nevertheless, the G-step Xeons are just a minor marker in Intel’s roadmap, whose next major milestone involves 45nm “Harpertown” Xeons and a new “Stoakley” platform designed to complement them.

Comments closed
    • smilingcrow
    • 12 years ago

    ‘including the ability to reach lower CPU multipliers and thus lower clock speeds’

    This is overdue with the 1333FSB chips idling at 2GHz. Does anyone know what the lowest multiplier is now? I hope they do the same for Penryn desktop chips although ES versions seem stuck on a lower multi of 6 still!

    • MixedPower
    • 12 years ago

    Who cares? Intel needs to work on the power consumption of the system as a whole. In Anand’s recent low-power server shoot-out they found that the Xeon only sipped half as much power as the Opteron. The real power-hungry components in the Intel system were the FB-DIMMs, using almost 70 watts compared to under ten watts for the AMD system, and the ‘unaccounted for’ section, which used up almost 90 watts compared to half of that number for AMD.

    §[<http://www.anandtech.com/IT/showdoc.aspx?i=3039&p=2<]§

      • continuum
      • 12 years ago

      That is definitely true, but this is a nice step in that direction– particularly for places that are already locked into Intel (or vice versa, for AMD) chips for the high-precision operations they do– such as many of our customers.

      • blastdoor
      • 12 years ago

      I totally agree. I don’t understand why Intel saddles Xeon with FB-DIMMs. Certainly it’s fine to offer it as an option to those who need it, but why force it on everyone who wants a 2 socket system?

      This is one of the few remaining glaring blind spots for Intel. I can imagine that Barcelona will do relatively well if it’s in the same ballpark as Xeon performance-wise, just because people will want to avoid FB-DIMMs.

    • swaaye
    • 12 years ago

    Wasn’t that going to be the huge draw for Barcelona? Its low power usage. With the low clock launch coming up it certainly wasn’t going to be raw performance. Hmmm. Well AMD should still have the lower power system platform, I think.

      • SPOOFE
      • 12 years ago

      A lot of things were supposed to be the huge draw for Barcelona. Performance, cost, and the very fate of humanity have been, at varying points, reasons to wait for Barcelona.

      • green
      • 12 years ago

      the draw is supposed to be that barcelona will have the same TDP as the current generation dual core variants

        • SPOOFE
        • 12 years ago

        That’s not terribly informative. That can range anywhere from 65w to 125w. The former would be excellent, but the latter would be yawners.

          • green
          • 12 years ago

          no it isn’t and that’s because of amd’s language
          they say “quad cores will keep the same power envelopes as their dual-core counterparts”
          of course they don’t say if that’s at the same clock speed
          which i’d say the general population would have assumed is true

          pretty easy for a quad core to have a 65w tdp…. clocked at 1.x ghz….

    • LookngIntheVoid
    • 12 years ago

    Tech wise they should be better. With better stepping and powersavings.
    Barcelona core has seperate stepping for each core, which is better than Intel quad has.
    e.g.
    Barcelona need only 1 core at full load, and the rest idle it can reduce power, stepping, and power for memory controller.
    Intel quad needs at least 2 core working at higher stepping (when 1 core is needed), all 4 cores when 2-3 are needed (and full power to the frontside bus (then 1333mhz bus is even worse than the 1066mhz one)).

    2Ghz Barcelona vs. 2Ghz Core Duo Quad (1066 or 1333Mhz bus) the Barcelona should use least amount of power (with a wise chipset choice e.g. non-nvidia)

    (funny how 1333mhz frontside on the Core Duo reduces performance 1pct with ddr3, sad way to loose money)

      • SPOOFE
      • 12 years ago

      Barcelona HAS – present tense – nothing, since as far as products go, it doesn’t exist yet. What it may HAVE – future tense – is still up in the air.

    • Lord.Blue
    • 12 years ago

    DAAMIT had better hope that the Barcelona has at least similar power sippage.

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