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 ESTThe activity cited most often for improved memory speeds is IGP gaming, and as shown in both of our tests of Crystalwell (4950HQ in CRB, 4750HQ in Clevo W740SU), Intel’s version of Haswell with the 128MB of L4 cache, having big and fast memory seems to help in almost all scenarios, especially when there is access to more and more compute units. In order to pinpoint where exactly the memory helps, we are reporting both average and minimum frame rates from the benchmarks, using the latest Intel drivers available. All benchmarks are also run at 1360x768 due to monitor limitations (and makes more relevant frame rate numbers).
Bioshock Infinite: Average FPS
Average frame rate numbers for Bioshock Infinite puts a distinct well on anything 1333 MHz. Move up to 1600 gives a healthy 4-6% boost, and then again to 1866 for a few more percent. After that point the benefits tend to flatten out, but a bump up again after 2800 MHz might not be cost effective, especially using IGP.
Bioshock Infinite: Minimum FPS
Unfortunately, minimum frame rates for Bioshock Infinite are a little over the place – we see this in both of our dGPU tests, suggesting more an issue with the title itself than the hardware.
Tomb Raider: Average FPS
Similar to Bioshock Infinite, there is a distinct well at 1333 MHz memory. Moving to 1866 MHz makes the problem go away, but as the MHz rises we get another noticeable bump over 2800 MHz.
Tomb Raider: Minimum FPS
The minimum FPS rates shows that hole at 1333 MHz still, but everything over 1866 MHz gets away from it.
Sleeping Dogs: Average FPS
Sleeping Dogs seems to love memory – 1333 MHz is a dud but 2133 MHz is the real sweet spot (but 1866 MHz still does well). CL seems to make no difference, and after 2133 MHz the numbers take a small dive, but back up by 2933 again.
Sleeping Dogs: Minimum FPS
Like the average frame rates, it seems that 1333 MHz is a bust, 1866 MHz+ does the business, and 2133 MHz is the sweet spot.
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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!