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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  • Kevin G - Monday, July 25, 2011 - link

    One thing worth noting is that the memory controller has to run at least twice the clock speed of the memory (ie, the memory controller runs at 3.2 Ghz for 1600 Mhz DDR3 rated memory). This is one of the reasons why Intel doesn't officially support memory speed higher than 1600 Mhz. Running the CPU cores and memory controller at the same clock speed should produce a benefit even if memory speed isn't improved (ie running the CPU and memory controller at 4.8 Ghz with 1600 Mhz memory). It would be interesting to see how just scaling the memory controller's speed affected performance.

    I wish that their were a few game tests utilizing the integrated GPU. For a desktop, using a discrete graphics card for gaming is a new brainer over Intel's integrated graphics. However many laptops will only use Intel's solution and thus improving memory performance could be a means of improving gaming performance here. Further more, laptops are often lower resolution than 1920 x 1080 and thus the performance delta between memory speeds would be wider.
    Reply
  • RussianSensation - Monday, July 25, 2011 - link

    But even if laptops run at lower resolutions, they have much weaker CPUs and GPUs and generally have slow 5400 rpm hard drives. So if anything, memory speed will be even less important in a laptop since a laptop will be faced with all kinds if I/O, GPU and CPU bottlenecks.

    Improving performance of Intel's gaming solution with faster memory is a waste of time. HD3000 is just a dog. If you want a budget gaming laptop, you get Llano. No amount of memory bandwidth is going to translate into a more playable gaming experience on the HD3000.
    Reply
  • Kevin G - Monday, July 25, 2011 - link

    Except that Llano is in the same situation as it too needs fast memory for better graphics performance. If DIMM manufacturers start rolling out high performance memory for Llano, Sandy bridge laptops can also benefit. So why not actually test to see what those benefits could be? Reply
  • orenlevy - Tuesday, July 26, 2011 - link

    there is defenetly gpu improvment on hd3000 i dont know why you are not benching on Z68 platform. personally i have z68 htpc and sure i noticed different lateness on normal use. we always like sppedy windows poping and that simply whats happans.
    personally i say to myself "oh its about time to squeez little bit more from the sandybridge" even the G840 behave so different on 1600M cl8 Z68...
    Reply
  • jabber - Monday, July 25, 2011 - link

    As its such a waste of life. RAM hasnt been fun or that important since the good old DDR days.

    They may as well just hardwire 4GB of bog standard ram onto the motherboard for most folks.
    Reply
  • silverblue - Monday, July 25, 2011 - link

    Maybe they have, but RAM speed is important for iGPUs and especially so for APUs.

    For those wondering where the Llano equivalent is...

    http://www.anandtech.com/show/4476/amd-a83850-revi...
    Reply
  • silverblue - Monday, July 25, 2011 - link

    Duh. The link is on the final page of this article. Reply
  • Kevin G - Monday, July 25, 2011 - link

    The main reason why RAM still comes on DIMMs is due to reliability and the need for expansion. Cost is also a factor, especially for motherboards with lot of RAM soldered on to it.

    However, soldering down RAM in some situations does make sense. Expandability in laptops for example. Another area where soldiered RAM on a desktop motherboard would make sense is with the overclocking crowd. The RAM could be placed closer to the CPU socket which could easily increase clock speeds. The elimination of the edge connector on the DIMM would also significantly enhance signal strength too. Physical placement on the motherboard would allow for better cooling (larger heat sinks or water cooling with direct contract with the RAM chips). There would also be room for robust power delivery to the RAM chips on the motherboard.
    Reply
  • dac7nco - Monday, July 25, 2011 - link

    I' glad there are still RAM reviews; 1.5v DDR3 1600 / CAS 7/7/7 gets me an additional 1 to 2 FPS in long Handbrake transcodes, which is a big part of my bread and butter.

    Keep in mind, 1.5v, no higher, is the DDR3 spec, which is why you'll never see ECC DDR3 registered memory rated above that. Keep this in mind, Anand: Control your people! X58-rated memory has no place today.

    Daimon
    Reply
  • jabber - Monday, July 25, 2011 - link

    I still think the main selling pint for RAM is - How well does it match my motherboard?

    Maybe a round up of modules with fancy spreaders and how they look in Asus/Gigabyte/Asrock/MSI boards.
    Reply

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