Memory Scaling on Haswell CPU, IGP and dGPU: DDR3-1333 to DDR3-3000 Tested with G.Skill
by Ian Cutress on September 26, 2013 4:00 PM ESTEnabling XMP with ASUS, GIGABYTE, ASRock and MSI on Z87
By default, memory should adhere to specifications set by JEDEC (formerly known as the Joint Electron Device Engineering Council). These specifications state what information should be stored in the memory EEPROM, such as manufacturer information, serial number, and other useful information. Part of this are the memory specifications for standard memory speeds, including (for DDR3) 1066 MHz, 1333 MHz and 1600 MHz, which a system will adhere to in the event of other information not being available.
An XMP, or (Intel-developed) Extreme Memory Profile, is an additional set of values stored in the EEPROM which can be detected by SPD in the BIOS. Most DRAM has space for two additional SPD profiles, sometimes referred to as an ‘enthusiast’ and an ‘extreme’ profile; however most consumer oriented modules may only have one XMP profile. The XMP profile is typically the one advertised on the memory kit – if the capability of the memory deviates in any way from specified JEDEC timings, a manufacturer must use an XMP profile.
Thus it is important that the user enables XMP! It is not plug and play!
At big computing events and gaming LANs there are plenty of enthusiasts who boast about buying the best hardware for their system. If you ask what memory they are running, then actually probe the system (by using CPU-Z), I sometimes find that the user, after buying expensive memory, has not enabled XMP! It sounds like a joke story, but this happened several times at my last iSeries LAN in the UK – people boasting about high performance memory, but because they did not enable it in the BIOS, were still running at DDR3-1333 MHz C9.
So enable XMP with your memory!
Here is how:
Step 1: Enter the BIOS
This is typically done by pressing DEL or F2 during POST/startup. Users who have enabled fast booting under Windows 8 will have to use vendor software to enable ‘Go2BIOS’ or a similar feature.
Step 2: Enable XMP
Depending on your motherboard manufacturer, this will be different. I have taken images from the major four motherboard manufacturers to show where the setting is on some of the latest Z87 motherboard models.
On the ASUS Z87-Pro, the setting is on the EZ-Mode screen. Where it says ‘XMP’ in the middle, click on this button and navigate to ‘Profile 1’:
If you do not get an EZ mode (some ROG boards go straight to advanced mode), then the option is under the AI Tweaker tab, in the AI Overclock Tuner option.
For ASRock motherboards, navigate to OC Tweaker and scroll down to the DRAM Timing Configuration. Adjust the ‘Load XMP Setting’ option to Profile 1.
For GIGABYTE motherboards, such as the Z87X-UD3H in the new HD mode, under Home -> Standard is the separate XMP setting, as shown below:
Finally on MSI motherboards, select to the OC option on the left hand side and XMP should be in front of you:
I understand that setting XMP may seem trivial to most of AnandTech’s regular readers, however for completeness (and the lack of XMP being enabled at events it seems) I wanted to include this mini-guide. Of course different BIOS versions on different motherboards may have moved the options around a little – either head to enthusiast forums, or if it is a motherboard I have reviewed, I post up all the screenshots of the BIOS I tested with as a guide.
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Rob94hawk - Friday, September 27, 2013 - link
Avoid DDR3 1600 and spend more for that 1 extra fps? No thanks. I'll stick with my DDR3 1600 @ 9-9-9-24 and I'll keep my Haswell overclocked at 4.7 Ghz which is giving me more fps.Wwhat - Friday, September 27, 2013 - link
I have RAM that has an XMP profile, but I did NOT enable it in the BIOS, reason being that it will run faster but it jumps to 2T, and ups to 1.65v from the default 1.5v, apart from the other latencies going up of course.Now 2T is known to not be a great plan if you can avoid it.
So instead I simply tweak the settings to my own needs, because unlike this article's suggestion you can, and overclockers will, do it manually instead of only having the options SPD or XMP..
The difference is that you need to do some testing to see what is stable, which can be quite different from the advised values in the settings chip.
So it's silly to ridicule people for not being some uninformed type with no idea except allowing the SPD/XMP to tell them what to do.
Hrel - Friday, September 27, 2013 - link
Not done yet, but so far it seems 1866 CL 9 is the sweet spot for bang/buck.I'd also like to add that I absolutely LOVE that you guys do this kind of in depth analyses. Remember when, one of you, did the PSU review? Actually going over how much the motherboard pulled at idle and load, same for memory on a per DIMM basis. CPU, everything, hdd, add in cards. I still have the specs saved for reference. That info is getting pretty old though, things have changed quite a bit since back then; when the northbridge was still on the motherboard :P
Hint Hint ;)
repoman27 - Friday, September 27, 2013 - link
Ian, any chance you could post the sub-timings you ended up using for each of the tested speeds?If you're looking at mostly sequential workloads, then CL is indicative of overall latency, but once the workloads become more random / less sequential, tRCD and tRP start to play a much larger role. If what you list as 2933 CL12 is using 12-14-14, then page-empty or page-miss accesses are going to look a lot more like CL13 or CL14 in terms of actual ns spent servicing the requests.
Also, was CMD consistent throughout the tests, or are some timings using 1T and others 2T?
There's a lot of good data in this article, but I constantly struggle with seeing the correlation between real world performance, memory bandwidth, and memory latency. I get the feeling that most scenarios are not bound by bandwidth alone, and that reducing the latency and improving the consistency of random accesses pays bigger dividends once you're above a certain bandwidth threshold. I also made the following chart, somewhat along the lines of those in the article, in order to better visualize what the various CAS latencies look like at different frequencies: http://i.imgur.com/lPveITx.png Of course real world tests don't follow the simple curves of my chart because the latency penalties of various types of accesses are not dictated solely by CL, and enthusiast memory kits are rarely set to timings such as n-n-n-3*n-1T where the latency would scale more consistently.
Wwhat - Sunday, September 29, 2013 - link
Good comment I must say, and interesting chart.Peroxyde - Friday, September 27, 2013 - link
"#2 Number of sticks of memory"Can you please clarify? What should be that number? The highest possible? For example, to get 16GB, what is the best sticks combination to recommend? Thanks for any help.
erple2 - Sunday, September 29, 2013 - link
I think that if you have a dual channel memory controller and have a single dimm, then you should fill up the controller with a second memory chip first.malphadour - Sunday, September 29, 2013 - link
Peroxyde, Haswell uses a dual channel controller, so in theory (and in some benchmarks I have seen) 2 sticks of 8gb ram would give the same performance as 4 sticks of 4gb ram. So go with the 2 sticks as this allows you to fit more ram in the future should you want to without having to throw away old sticks. You could also get 1 16gb stick of ram, and benchmarks I have seen suggest that there is only about a 5% decrease in performance, though for the tiny saving in cost you might as well go dual channel.lemonadesoda - Saturday, September 28, 2013 - link
I'm reading the benchmarks. And what I see is that in 99% of tests the gains are technical and only measurable to the third significant digit. That means they make no practical noticeable difference. The money is better spent on a difference part of the system.faster - Saturday, September 28, 2013 - link
This is a great article. This is valuable, useful, and practical information for the system builders on this site. Thank you!