Does High-Speed DDR3 Help AMD's FX? Four 8 GB Kits, Reviewed

Making A Case For High-Speed RAM

The primary goal of today’s test was to find out if the reports of an AMD FX-based performance boost with high-speed RAM were true. The secondary goal was to find the best module set to get us that performance advantage. And while most of today’s benchmarks demonstrated negligible performance gains going from DDR3-1600 to DDR3-2400, one application really did jump by 6%. That’s a small gain in performance for such a big push in data rate, but it’s still noticeable. Dropping some of our RAM to CAS 6 at DDR3-1600 didn’t give us the same speed-up.

So, we know that the reports of improved Bulldozer performance with high-speed RAM are at least partly true, at least in certain types of applications. The next question is, which module set best gets us there?

This wasn’t supposed to be a value shootout, but one thing that a quick look at DRAM prices show is that only one of the top two module sets is currently available for purchase. The $25 price increase for G.Skill’s Ripjaws X DDR3-2133 would account for only 1% of a $2500 machine’s total price, and the RAM is capable of proving far more than 1% performance advantage in some applications.

Still, the best reason we can think of to buy high-end memory is to show off a big overclock. And so, a value chart that shows a maximum data rate divided by the baseline (DDR3-1600), compared to an actual price divided by the average price for all modules ($69), might not be all that important. Still, it’s nice to see that G.Skill holds its value when compared to top-brand DDR3-1600 CAS 9 modules.

A performance per price chart would be far more brutal to G.Skill, unless we add total system cost to the equation. The problem is, everyone's total system cost is likely to differ from ours. Parts like high-end cases and optical drives have no impact on today’s benchmarks, but would help make the case for G.Skill’s RAM by diminishing its relative price to the overall system.

Since high-speed memory only provides a marginal performance benefit to a small number of all the applications on your PC, we can only recommend the step up to a subset of enthusiasts willing to pay that extra money. At the end of the day, you will need to be the judge of whether or not the added expense is worth the marginal performance increase. Regardless, this was still a review of four high-performance memory kits, and G.Skill produced the best purchasable kit in this test. Therefore its Ripjaws X DDR3-2133 CAS 9 gets our stamp of approval.

Thomas Soderstrom
Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.
  • Rockdpm
    Interesting!. Still would wait for Pile driver. But since i do have a Kingston 8GB kit and a Sabertooth 990FX... may just have to try it one day
  • jdwii
    Great article this proves a lot of rumors!

    People can finally stop saying how unfair it is to test Amd with slower ram when it supports higher speed ram even though higher speed ram cost more money. It would actually be unfair to Intel its not their fault Amd needs higher speeds to compete(which it doesn't) with Intel's 1333 ram controller.

    Ram speeds do how ever make a big difference on APU's.
  • mayankleoboy1
    would love to see the same review for Ivy Bridge processors with and without iGPU HD4000.

    and do include more tests in the review.
  • sarinaide
    More of the cheap stuff is my mantra.
  • Crashman
    sarinaideMore of the cheap stuff is my mantra.Yeh yeh, but I really can't complain about paying $70 for 8GB of DDR3-2133, especially when it overclocks like that.
  • Reynod
    AMD has enjoyed the performance benefits of an integrated memory controller for more than twice as long as Intel. And yet, it seems that Intel sets today's standard for acceptability.

    Replace the last word with "performance" crash.

    Good article which gets answers a couple of questions people have been asking - well done !!

  • jaquith
    Thomas thanks for the review.

    First note:
    *KHX2400C11D3K4/8GX - is a Quad Channel kit specifically designed for the X79 ; link
    *WQ213UB4G vs WQ213UX16G (kit) - is ONE stick of RAM (not a matched kit) and its 'kit version' is Quad Channel kit specifically designed for the X79 ; link

    After that it makes sense that those (2) "kits" (in one case 4 individual sticks) failed @ Rated, and I wasn't interested in researching the others. I've seen other more in-depth testing on the AMD FX-8150 indicating that overall there's a slight advantage for the DDR3-1866 kits on a most of the AMD FX processors. Though @ 4AM 'to me' I'll edit this post after a few cups of coffee.

    The 'ideal' AMD kits have JEDEC 'SPD' @ Rated 'cloned' (XMP) encoding which is optimized for AMD and sometimes slightly different so you're not 'stuck' as you put it @ DDR3-1333. Those are the better KITS to test on the AMD FX lines.
  • SteelCity1981
    Ram sppeds on a Bulldozer CPU means little and this just proves that so it doesn't matter if you are using DDR3 1600 ram or buying high performance RAM that can overclock to DDR3 2800 your not really seeing hardly any improvement with Bulldozer by doing so.
  • bartholomew
    Good article, very informative!
    Thanks :)
  • RAM speed also has a HUGE impact in controlled cache environments:

    Even the best SSDs can barely muster 100,000 IOPs, yet even slow RAM can easily exceed 700,000 IOPs.
    Bandwidth, throughput, and latency are equally insane. RAM puts SSDs to shame exponentially more than SSDs put hard drives to shame. Contrary to what many "enthusiasts" believe, RAM timings are virtually irrelevant. Frequency is by far, much more important.