Final Words

I think we confirmed what we pretty much knew all along: Sandy Bridge's improved memory controller has all but eliminated the need for extreme memory bandwidth, at least for this architecture. It's only when you get down to DDR3-1333 that you see a minor performance penalty. The sweet spot appears to be at DDR3-1600, where you will see a minor performance increase over DDR3-1333 with only a slight increase in cost. The performance increase gained by going up to DDR3-1866 or DDR3-2133 isn't nearly as pronounced.

As a corollary, we've seen that some applications do react differently to higher memory speeds than others. The compression and video encoding tests benefited the most from the increased memory bandwidth while the overall synthetic benchmark and 3D rendering test did not. If your primary concern is gaming, you’ll want to consider investing in more GPU power instead of a faster system memory; likewise, a faster CPU will be far more useful than more memory performance for most applications. Outside of chasing ORB chart placement, memory is one of the components least likely to play a significant role in performance.

We also found that memory bandwidth does scale with CPU clock speed; however, it still doesn't translate into any meaningful real-world performance. The sweet spot still appears to be DDR3-1600. All of the extra performance gained by overclocking almost certainly comes from the CPU overclock itself and not from the extra memory bandwidth.

Finally, although the effects of low latency memory can be seen in our bandwidth tests, they don't show any real world advantage over their higher latency (ahem, cheaper) counterparts. None of the real-world tests performed showed any reason to prefer low latency over raw speed.

Even though there's merely a $34 price difference between the fastest and slowest memory tested today, I still don't believe there's any value in the more expensive memory kits on the Sandy Bridge platform. Once you have enough bandwidth (DDR3-1600 at a small $9-$10 price premium), there's just not enough of a performance increase beyond that to justify the additional cost, even when it's only $34 between 4GB kits. Once you jump to the 8GB kits, the price difference for CL9 DDR3-1600 is a mere $8, but it becomes much more pronounced at $92 to move to DDR3-2133. We simply can’t justify such a price difference based on our testing.

Of course, testing with Sandy Bridge doesn't necessarily say anything about other platforms. It's possible that AMD's Llano and Bulldozer platforms will benefit more from higher bandwidth and/or better latency memory, but we'll save that article for another day. Also, we've shown that performance scaling on integrated graphics solutions can benefit, particularly higher performance IGPs like Llano. Ultimately, it's up to you to choose what's best for your particular situation, and we hope this article will help you make better-informed decisions.

Memory Scaling with Overclocking
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  • Rick83 - Monday, July 25, 2011 - link

    Do they take into account, that we should be using 1.5V DIMMs for Sandy Bridge?

    The addition of that requirement usually limits choice quite a bit.
    Reply
  • compudaze - Monday, July 25, 2011 - link

    The SNB datasheet does suggest that the max memory voltage is 1.575V, however, many motherboard and memory manufactures state that they haven't had any problems with memory running at 1.65V on SNB. Reply
  • compudaze - Monday, July 25, 2011 - link

    Also, if you stick to the spec sheet, you shouldn't be running faster than DDR3-1333 memory. Reply
  • Taft12 - Monday, July 25, 2011 - link

    You should be using 1.5V DIMMs anyway - if a memory OEM needs 1.65V to achieve the same speed and timings another vendor does at 1.5V, it's inferior memory. Reply
  • jdogi - Monday, July 25, 2011 - link

    Just as your daily driver vehicle is likely inferior to a Mercedes or Ferrari. You should get a new car. You should not make any attempt to balance cost with the value. Just get the best. It's the only way to go. What's best for Taft is best for all.

    ;-)
    Reply
  • Iketh - Tuesday, July 26, 2011 - link

    you didn't understand the logic Reply
  • MrSpadge - Wednesday, July 27, 2011 - link

    I'm sure he did. What Taft failed to mention was that "at the same price, you should be using the memory spec'ed for less voltage". However, if some memory needs a little more voltage, but is way cheaper - balance cost and value.

    MrS
    Reply
  • Rick83 - Wednesday, July 27, 2011 - link

    Actually, the higher voltage is out of spec for the CPU memory controller and may wel impact longevity.
    So it's like buying the Ferrari, and running it on Biofuel with too much Ethanol that eats right through the tubing, but is marginally cheaper.
    Reply
  • jfelano - Tuesday, July 26, 2011 - link

    Not inferior, just older. All 1600mhz memory was 1.65v when it debuted. Then they came out with 1.5v, now even 1.35v. Reply
  • cervantesmx - Thursday, July 28, 2011 - link

    That is correct indeed. Just purchased 8GB at 1600mhz running on 1.25v. $59.99. Free shipping. Reply

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