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Four High-End Quad-Channel DDR3 Memory Kits For X79, Reviewed

Overclocking And Under-Latency Results

Only two of the memory kits in today’s round-up are rated at DDR3-2400, while others list DDR3-2133 as their top validated data rate. So how many kits are actually capable of pushing the high mark on our motherboard?

Corsairs 8 GB kit barely exceeded expectations, while RipjawsZ fell slightly below them. In spite of that, G.Skill’s kit is still the fastest among 16 GB competitors.

Ergo our caveats, the first of which is that many Sandy Bridge-E-based processors can’t reliably run at DDR3-2400. Our first Core i7-3960X wouldn’t reach this frequency at any setting, and its replacement is barely any better in this regard (though its higher-attainable core speed does make motherboard testing easier).

The second caveat comes from Asus, which informed us that CPU VCCA (formerly referred to as uncore) voltage probably shouldn’t exceed 1.20 V. According to them, some processors lose stability and may even be damaged at higher settings, while others do not or will not. Ours reached the highest memory settings using 1.20 to 1.25 V.

Our third caveat is that different memory firms use different CPU samples to determine the best settings for their own memory, and those settings might not be right for your CPU. Corsair, for example, included VCCA of 1.40 V in its XMP profile, but wouldn’t overclock well until we dropped it to 1.25 V. Likewise, G.Skill’s 1.20 V XMP VCCA worked perfectly with our CPU, but probably wouldn’t work well with whatever CPU the folks at Corsair used to dial in their profile.

None of the DDR3-2133 samples include VCCA in their XMP profiles, likely because the CPU’s memory controller only needs this adjustment at extremely high data rates.

Best Timings at 1.65 V
DDR3-2400DDR3-2133DDR3-1866DDR3-1600
Corsair Dominator GT CMGTX8 (4 x 2 GB)10-12-10-129-10-9-108-9-8-97-8-7-8
G.Skill Ripjaws Z F3-19200CL9Q-16GBZHD8-10-9-107-9-8-96-7-7-7
Geil Evo Corsa GOC316GB2133C9AQC9-11-9-118-9-8-97-8-7-8
Mushkin Redline 9939979-10-9-288-9-8-97-8-7-8

Corsair has the best DDR3-2400 timings, though this is likely a result of its lower-density 8 GB kit. Our CPU sample, hand-picked for its overclocking headroom, couldn’t handle the larger, higher-density 16 GB kits at this frequency. That also eliminates any DDR3-2400 performance testing, since we’d need at least two devices to compare.

G.Skill takes over from DDR3-2133 downward, its 16 GB kit pushing 1-cycle lower CAS at every tested frequency, compared to competitors.

  • a4mula
    The article seems supports the same basic premise we've since at least the bclk limited 1155. Even with the 125 and 166 straps added to LGA2011 there is still too little base clock manipulation available push memory very far.

    Performance gains via memory even when given a favorable playing field (reduced graphics) are pretty small. The reference CAS 9 1600 appeared to hold its own at a fraction of the cost. As was eluded to I think kits like this are really only aimed towards the small crowd of super-enthusiasts that want to squeeze every last drop out of a system regardless of price.

    Nice article and one that I think illustrates both the benefits (ease of overclocking) and disadvantages (less fine tuning) of the multiplier friendly yet limited bclk of both 1155 and 2011.
    Reply
  • panderaamon
    I'll take 8 GB per slot Ram's for my X79 thank you very much.

    Also it would have been nice to add some Ram Disk benchmarks to the review aswell.
    Reply
  • bauboni
    It would be nice to compare these 2.4Ghz Quad Channel memories with the usual 1.6Ghz DualChannel kits, specialy at gamming scenarios.
    Reply
  • Crashman
    a4mulaThe article seems supports the same basic premise we've since at least the bclk limited 1155. Even with the 125 and 166 straps added to LGA2011 there is still too little base clock manipulation available push memory very far. The board supports DDR3-2400 data rate, limitations on this CPU's memory controller made it impossible for most modules to reach that setting. You can underclock or overclock the base clock by a wide enough margin to fill the holes between 2133 and 2400, etc.
    bauboniIt would be nice to compare these 2.4Ghz Quad Channel memories with the usual 1.6Ghz DualChannel kits, specialy at gamming scenarios.That's why there's a DDR3-1600 reference data set on each chart. Of course it's quad-channel because that's what the CPU is designed to run, and we wouldn't want to artificially handicap it...would we?
    Reply
  • noob2222
    Where is AMD's memory testing? Since SB-E was mostly SB, memory already wasn't expected to improve much. http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/6

    SB-E hasn't changed much here, at most ~1% boost.
    Reply
  • bauboni
    CrashmanThe board supports DDR3-2400 data rate, limitations on this CPU's memory controller made it impossible for most modules to reach that setting. You can underclock or overclock the base clock by a wide enough margin to fill the holes between 2133 and 2400, etc.That's why there's a DDR3-1600 reference data set on each chart. Of course it's quad-channel because that's what the CPU is designed to run, and we wouldn't want to artificially handicap it...would we?
    Well, I really wanted to see the practical difference between dual to quad channel at gamming =P
    Reply
  • Crashman
    panderaamonI'll take 8 GB per slot Ram's for my X79 thank you very much.Also it would have been nice to add some Ram Disk benchmarks to the review aswell.The reason you didn't see 16GB kits in the past is that Tom's Hardware has always had trouble finding "widespread" applications that could benefit from more than 8GB. RAMDISK is an interesting option for eight-DIMM motherboards because 64GB can be employed. That would be really handy for a 48GB RAMDISK and 16GB of free memory!

    Of course we'd like to gauge the marketability of this concept before putting money behind it, so perhaps you can start a thread in the Forums to gauge its popularity? On a platform limited to $500-1000 CPU's, would any readers really spend that much a second time for memory?
    Reply
  • CaedenV
    so... while there are differences in synthetic tests, there is no practical difference between 1600 and 2133 (and in some cases a negative effect). A bit disappointing, but it does follow previous test results.
    Just wondering, but does this mean there is a bottleneck in the CPU? Is OCing the ram worth it when paired with a 5ghz processor? It is just hard to suggest any of these products when there is so little difference between them and the stock version. Good article though
    Reply
  • CaedenV
    CrashmanThat would be really handy for a 48GB RAMDISK and 16GB of free memory!Of course we'd like to gauge the marketability of this concept before putting money behind it, so perhaps you can start a thread in the Forums to gauge its popularity? On a platform limited to $500-1000 CPU's, would any readers really spend that much a second time for memory?I have always wanted a RAM disc simply due to the slow seek speed of HDDs, but now with SSDs available (and doping in price like a rock) it simply makes sense (and ease of use) to use an SSD or SSD RAID instead. Sure, system RAM is still faster, but SSDs take the cake for speed/size/performance for most applications where a ram disc would have previously had a sizable advantage. Ram discs still have a home in servers, but for video/audio/3d work on a workstation I think the money would be better spent elsewhere.
    All the same I would love to be proved wrong and see some real world tests on the subject!
    Reply
  • theuniquegamer
    I haven't expected that the price of quad channel Rams will be such a premium price like the gskill ripjaw
    Reply