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AMD Releases FX-Series Bulldozer Desktop CPUs

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  • #81
    Originally posted by Kivada View Post
    Maybe it's because you forget that loading from the CPU cache is faster then loading from system ram? If I remember right since it's been a few years, if all other things are equal doubling the amount of CPU cache should improve performance by 3-5% across the board, so those of you claiming that it might perform better without the L3 cache are basing your arguments on what exactly?

    Cache is only faster if it's being used. Adding more cache doesn't automatically add 3-5% across the board. That's an estimate, because most apps used to use the extra cache about that much. As caches grow larger, the number of apps that can take advantage of it but didn't previously will decrease. And note that rule of thumb is talking about doubling the amount of cache (in the same level) which means there is no additional latency involved that wasn't already there. In this case, you are adding an entire additional level of cache, increasing latencies, which means that some of the speedup is then offset by that slowdown.

    Some apps will get no gain at all while others will see massive gains. It all depends on their memory usage patterns. If they are randomly accessing memory, no amount of cache will help because nothing is cached the first (and last) time you access it. On the other hand, if you have an app that really needs to frequently access < 8MB of data but > 1MB, this extra cache is going to be a huge help. Lots of server apps fall under that category. Not many desktop apps. L3 cache is also used in modern designs to directly share data across multiple cores - which again is more relevant to server workloads than a desktop one.

    I'm not saying the extra L3 cache is actually hurting anything in these tests. I'm just saying it might be. At least in some of them - I'm sure it's helping in a few as well.

    I know a lot of games, for example, are extremely dependent on memory access timings. They loved the fast L2 speeds the old Pentium M and later Core processors had, and didn't particularly take advantage of the L3 cache Phenoms added.

    AMD has already said they are planning to release a Bulldozer chip with the L3 cache removed or reduced for the consumer market, so they know all of this far better than you or i do. I'm not sure when it will come out, but my guess is that all non FX series will probably have it removed.

    As before, these weren't designed for the desktop market, because CPU performance on the desktop as been "good enough" for several years now, servers are where the money is these days, so theres point in designing a CPU specifically for the consumer market when your server CPU will work just fine for the task, thus why bother pouring time and money into chasing a stagnant market where the difference in perceived performance by the end user will essentially be identical to those using a machine from 2006?
    Like i said, this chip was designed for the server market. That comes with both positive and negatives to it.

    Seriously, put any of your non tech relatives in front of a machine with a Core2 or Athlon2 system and an i5 or i7, can they tell the difference, especially if both machines have identical graphics drivers and amounts of ram? My guess would be no, they can't tell the machines apart, the seconds saved off by the i7 in their day to day tasks would be completely unnoticed. Welcome to 95% of the computing market. Seriously, they are either suffering with a terrible GPU and no SSD, having those would have a more noticeable impact then a faster CPU.
    I never even made this argument, so i'm not sure why you're trying to argue a point that i agree with.
    Last edited by smitty3268; 17 October 2011, 05:31 AM.


    • #82
      Coming from a noob, shouldn't it be a positive effect when the whole binary fits to the cache?


      • #83
        Originally posted by Kivada View Post
        I'd love to support VIA, but I run Linux and they seem to be too retarded to realize their own position and should have merged with Nvidia long ago for the benefit of both companies. Its one of the few times you'll ever hear me support a merger, because I liked what was demoed with the VIA Nano CPU with the Nvidia ION chipset and Nvidia would have had access to their X86 license and stable of ARM devs. Though I still don't like that Nvidia wont release docs to the Nouveau team, I'll take OSS drivers over blobs any day of the week.
        I'd be happy with VIA not doing a 180 on us after promising full OSS IGP drivers.
        Their dual-core Nano is actually pretty good, and chrome IGPs are more than enough for entry-level parts. The openchrome drivers offer better video playback than VIA's own "compile 6-months late stuff yourself" code. The only things the latter have going for themselves is 3D hardware acceleration and better management of external display. Although setting it up is a major PitA.
        Oh and they've had on-die AES support since at least the C7 days (I should know, I own an HP2133), although people seem to think Intel got there first.

        Back to OT, again I think people should stop crying murder and give BD a chance. It's off a disappointing (to put it mildly) start since initial tests have made it look like far from an clear-cut upgrade from previous AMD CPUs. I still think the basis for the architecture is sound and it's gonna turn out to be a really fine option real soon.

        That, and the people who put together the press kit for the launch should be shot. Not fired, shot. Right between the eyes. Though I could settle for "neutered".


        • #84
          Originally posted by smitty3268 View Post
          power requirements,
          Bingo was his namo.


          • #85
            Compiler will help with multithreaded performance