The Return of Hyper Threading

While Nehalem is designed to scale to up to 8 cores per chip, each one of those cores has the hardware necessary to execute two threads simultaneously - yep, it's the return of Hyper Threading. Thus our quad-core Nehalem sample appeared as 8 logical cores under Windows Vista:


Four cores, eight threads, all in a desktop CPU

Note that as in previous implementations of Hyper Threading (or other SMT processors) this isn't a doubling of execution resources, it's simply allowing two instruction threads to make their way down the pipeline at the same time to make better use of idle execution units. Having 8 physical cores will obviously be faster, but 8 logical (4 physical) is a highly power efficient way of increasing performance.

We took Valve's source-engine map compilation benchmark and measured the compile time to execute one instance (4 threads) vs. two instances of the benchmark. The graph below shows the increase in compilation time when we double the workload:

Valve Map Compilation Benchmark - 4 to 8 Thread Scaling

While the 2.66GHz Core 2 Quad Q9450 (Penryn) takes another 127 seconds to execute twice the workload, the 2.66GHz Nehalem only needs another 49 seconds. And if you're curious, this quad-core Nehalem running at 2.66GHz is within 20% of the performance of an eight-core 3.2GHz Skulltrail system. Equalize clock speed and we'd bet that a quad-core Nehalem would be the same speed as an 8-core Skulltrail here. The raw performance numbers are below:

Valve Map Compilation Benchmark 

We couldn't disable Hyper Threading so we reached the limits of what we were able to investigate here.

The Socket A Quick Path to Memory
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  • Poepstamper - Thursday, June 5, 2008 - link

    im not a fanboy but i like AMD better,i dont like big corporations anyways.
    but im pretty worried if AMD has no answer to this,then we would have to pay lots more for a processor.
  • Genx87 - Thursday, June 5, 2008 - link

    Being an AMD fan and sometimes fanboi over the past 12 years. My last major game rig build was a Core 2 Duo 6600. I did an upgrade 3 weeks ago with an E8400. I built a new computer for a friend who has had AMD chips since 1999 with an E7200.

    AMD needs to start making a show.
  • NullSubroutine - Thursday, June 5, 2008 - link

    First off, I am not a fan of either company, just to get that out of the way.

    You do realize that Nehalem is not or will not be a mainstream product for quite some time into 2009. Enthusiast may get a few chips in limited quantities, probably in the $1500+ range. Otherwise this is designed to be a high end Server processor. It will take some time for it to trickle down to be something most average people will buy and use.

    Intel is hitting back the same way AMD hit at Intel back with the K8. Making a great scaleable high performance server chip and letting it trickle its way down to the mainstream market.

    Trying to compare Nehalem to any AMD processor (or even most Core2/quad) is like trying to compare a Chevy Mailibu to a Formula 1 race car, its just not the same thing.

    What is exciting about Nehalem right now is the technological advancement of some of the stuff Intel has done, and the happiness that it will one day be availble mainstream.

    AMD is not going to be put in a bad position (other than the one its already in) in the mainstream desktop market with Nehalem - not for probably near another year. It will hurt it in the Server market, but at first Intel wont have many of these chips availible, so AMD will have a minor chance with a Shanghai or Bulldozer core - if they can actually execute a launch.

    AMD is also not trying to stay equal with Intel, it doesnt have the resources to do it. You are likely, in any near time frame, going to see AMD come out and just PWN Intel in performance numbers. You will see AMD put together what they call a good 'platform' meaning. You can buy your whole platform, MB/CPU/GPU/etc from AMD and it will be a solid platform.

    It's not going to win bragging rights to a bunch of 'nerds' running gaming websites claming how AMD sucks so much. You will probably see that actually, people saying how 1500 dollar processor pwns some 200 dollar one. AMD isnt currently trying to win performance crowns or win over enthusiast that spend boat loads of money on a CPU (or GPU) they are trying to push the mainstream market, which actually has the largest number of people to sell to. However I am sure they would like to keep their server side doing well (it makes good margins).

    I don't think you are going to see an AMD come back to any pure performance crowns. You may some crowns for price/performance/power for the whole platform.
  • NullSubroutine - Thursday, June 5, 2008 - link

    supposed to say You are NOT likely to see AMD come PWN Intel...

    And you could compare 8 series Opteron to Nehalem...
  • AmberClad - Thursday, June 5, 2008 - link

    That picture of the socket -- I only recall a single board with that colored PCB in the INQ's coverage of the wall of Nehalem boards. Maybe that picture is giving away more than intended, as far as the identity of the company that provided the sample? (I suppose it's possible that whoever leaked the Nehalem sample isn't the same person that provided the motherboard.)
  • RaynorWolfcastle - Thursday, June 5, 2008 - link

    These benches are mighty impressive for such an immature platform. There had better be some serious performance and clock speed bumps in store for AMD's K10.5 or they will be dead in the water.

    Also, is there any indication as to when Intel will start transitioning Nehalem to the mobile space? I have a 1st gen (Core Duo) MacBook Pro that's getting a little long in the tooth and I'm debating whether to jump on the Montevina train or wait for Nehalem mobile. I'd love to get a mobile Nehalem if it launches any time in 1H09.
  • emboss - Friday, June 6, 2008 - link

    Non-Extremely-Expensive-Edition single-socket Nehalems now aren't coming until sometime in 2H09, so you'll probably be lucky to see any mobile Nehalems in 2009 at all.

    As such, I'd say Intel failed to tick on time. Conroe hit mainstream July 06 (eg: E6400). We should be getting mainstream Nehalems in 1 month, not 12+ months.

    Then again, Intel has been futzing around with the release dates quite a bit, so it may get pulled forward.
  • piroroadkill - Thursday, June 5, 2008 - link

    Because Nehalem is frankly so much faster than the already rapid Core 2, that as already said, AMD is going to be struggling for a long time to come.

    Unless some miracle occurs, all I know is right now I want Nehalem.
  • TonyB - Thursday, June 5, 2008 - link

    can it play crysis
  • PeteRoy - Thursday, June 5, 2008 - link

    Exactly, where are the gaming performance? It's the first thing I care about by a long way.

    I don't do all the other stuff you benched on my PC.

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