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. When Core i7 (the Bloomfield version) launched with 1.65 V as its recommended maximum voltage, manufacturers divided their DDR3 DRAM across two product lines: higher-voltage AMD and lower-voltage Intel products.
Of course, appearances can deceive. When it comes to product development and (especially) marketing, this editor takes very little of what he sees at face value. Tom’s Hardware had already tested 1.50 V performance RAM many months before Intel’s original Core i7 launch, watched as manufacturers began making switching to smaller manufacturing processes (yielding less voltage-tolerant memory), and knew that DDR3 memory running at DDR2 voltage levels would soon be a thing of the past. Eventually, vendors with large inventories of older high-voltage ICs began marketing those sometimes-inferior products to enthusiasts with AMD CPUs because they could tolerate the abuse, all the while branding their new and improved products as Intel-optimized.
EPP, XMP, and AMD
Memory must be bootable at motherboard-default voltage levels, defined by JEDEC as 1.50 V for DDR3 modules, in order to assure compatibility across multiple platforms. A tiny flash ROM (called an SPD) on each module tells the motherboard how fast (or slow) the memory needs to be configured in order to run at JEDEC-defined voltage.
The use of higher-than-standard voltage levels to reach higher performance levels is overclocking. So, most of what we refer to as performance memory is actually rated for overclocked settings.
EPP made memory overclocking easy, at least on many DDR2 platforms.
Many folks are simply too risk-adverse to start overclocking components manually. So, Corsair and Nvidia developed a method to do it semi-automatically. Released upon the world for all to play with, Enhanced Performance Profiles were memory configuration tables added to a slightly higher-capacity version of the SPD ROM. With this technology enabled, users could pick a complete memory overclock in BIOS. Since EPP was co-developed by former chipset manufacturer Nvidia, most of the motherboards that supported it had Nvidia chipsets.
A bad EPP 2.0 reading for 1.80 V RAM, taken from an XMP-specific motherboard.
But that was back in the days of DDR2. When Intel came out with a similar technology called eXtreme Memory Profiles for DDR3, the new technology was quickly added to user-configurable Intel-chipset motherboards. Corsair countered with EPP 2.0 for DDR3, but Intel’s dominance over its own platforms meant that the newer, lower-voltage Intel-oriented RAM shipped exclusively with XMP.
Aeneon’s attempt to combine EPP 2.0 and XMP on the same modules.
EPP 2.0 disappeared as supplies of the older high-voltage memory dwindled, and AMD-specific memory disappeared with it. All of today’s test modules have XMP profiles, and those profiles are displayed (but not selectable) in our motherboard’s firmware.
- Does Faster RAM Improve The Performance Of AMD FX CPUs?
- Does AMD-Optimized Memory Still Exist?
- G.Skill Ripjaws X F3-17000CL9D-8GBXM
- Kingston HyperX KHX2400C11D3K4/8GX
- Super Talent Quadra Series WQ213UB4G
- Team Xtreem LV TXD38192M2800HC11RDC-L
- Test Setup And Benchmarks
- Overclocking And Under-Latency Results
- DDR3-1600 Performance
- DDR3-1866 Performance
- DDR3-2133 Performance
- DDR3-2400 Performance
- Making A Case For High-Speed RAM
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.
Notice in the chart you showed, the difference between 2133 and 1866 is rather small. The baseline in this test was DDR3-1600 CAS 9 because that's the slowest memory a performance builder would use. In other words, the 1333 and 1066 results are irrelevant.
The benefit you're seeing in some articles is reduced real-time latency, which I'm fairly certain is discussed in this article. DDR3-1333 CAS 7 has the same real-time latency as DDR3-2666 CAS 14, since the cycle time is inverse of frequency.
If we assume for only a moment that DDR3-1600 is barely fast enough to fill the bandwidth needs, most of the difference over 1600 actually measures how long the CPU is waiting for instructions. Now I wouldn't actually assume 1600 is enough, I only assume that 1600 is the minimum speed that goes into most performance builds. After all, who would buy 1333 to save money in a performance machine when 1600 is so cheap?
and do include more tests in the review.
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.
and do include more tests in the review.
Replace the last word with "performance" crash.
Good article which gets answers a couple of questions people have been asking - well done !!
First note:
*KHX2400C11D3K4/8GX - is a Quad Channel kit specifically designed for the X79 ; link http://www.kingston.com/us/company/press?pagename=n1111c&year=2011&prLanguage=english_emea
*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 http://www.supertalent.com/datasheets/WQ213UX16G.pdf
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.
Thanks
http://thessdreview.com/our-reviews/romex-fancycache-review-ssd-performance-at-13gbs-and-765000-iops-in-60-seconds-flat/
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.
It's like putting a diamond in an aluminum ring. It makes no sense.
http://media.bestofmicro.com/G/Y/327202/original/sandra%20mem.png
amd apus are different story. those perform better in games with faster memory.
only posted in case some wonder how much intel gets out of rams.
This article proves one thing, not every program responts to memory speed.
http://vr-zone.com/articles/amd-fx-8150-memory-scaling-investigation--feeding-the-bulldozer/13704.html
http://www.madshrimps.be/articles/article/1000220/AMD-FX-8150-Bulldozer-CPU-Review/4#axzz1wX1gAnfF
Ill match your 4 cherry picked benchmarks against 2 websites that state otherwise.
Throw civ V into the mix and your way off.
Please, at least try to be honest. You already knew the Madshrimps article was explicitly dishonest because it used CAS 8 timings at all speeds (even 2133). Real-world memory supports tighter timings at lower frequencies, and requires looser timings at higher speeds. Madshrimps gimped the low-speed tests and boosted the high speed configuration intentionally.
Notice in the chart you showed, the difference between 2133 and 1866 is rather small. The baseline in this test was DDR3-1600 CAS 9 because that's the slowest memory a performance builder would use. In other words, the 1333 and 1066 results are irrelevant.
The benefit you're seeing in some articles is reduced real-time latency, which I'm fairly certain is discussed in this article. DDR3-1333 CAS 7 has the same real-time latency as DDR3-2666 CAS 14, since the cycle time is inverse of frequency.
If we assume for only a moment that DDR3-1600 is barely fast enough to fill the bandwidth needs, most of the difference over 1600 actually measures how long the CPU is waiting for instructions. Now I wouldn't actually assume 1600 is enough, I only assume that 1600 is the minimum speed that goes into most performance builds. After all, who would buy 1333 to save money in a performance machine when 1600 is so cheap?
the problem is both of those games, dirt 3 and metro 2033 are gpu limited. http://www.techspot.com/review/403-dirt-3-performance/page7.html