Choosing a Gaming CPU: Single + Multi-GPU at 1440p, April 2013
by Ian Cutress on May 8, 2013 10:00 AM ESTDiRT 3
DiRT 3 is a rallying video game and the third in the Dirt series of the Colin McRae Rally series, developed and published by Codemasters. DiRT 3 also falls under the list of ‘games with a handy benchmark mode’. In previous testing, DiRT 3 has always seemed to love cores, memory, GPUs, PCIe lane bandwidth, everything. The small issue with DiRT 3 is that depending on the benchmark mode tested, the benchmark launcher is not indicative of game play per se, citing numbers higher than actually observed. Despite this, the benchmark mode also includes an element of uncertainty, by actually driving a race, rather than a predetermined sequence of events such as Metro 2033. This in essence should make the benchmark more variable, but we take repeated runs in order to smooth this out. Using the benchmark mode, DiRT 3 is run at 1440p with Ultra graphical settings. Results are reported as the average frame rate across four runs.
One 7970
While the testing shows a pretty dynamic split between Intel and AMD at around the 82 FPS mark, all processors are roughly +/- 1 or 2 around this mark, meaning that even an A8-5600K will feel like the i7-3770K.
Two 7970s
When reaching two GPUs, the Intel/AMD split is getting larger. The FX-8350 puts up a good fight against the i5-2500K and i7-2600K, but the top i7-3770K offers almost 20 FPS more and 40 more than either the X6-1100T or FX-8150.
Three 7970s
Moving up to three GPUs and DiRT 3 is jumping on the PCIe bandwagon, enjoying bandwidth and cores as much as possible. Despite this, the gap to the best AMD processor is growing – almost 70 FPS between the FX-8350 and the i7-3770K.
Four 7970s
At four GPUs, bandwidth wins out, and the PLX effect on the UP7 seems to cause a small dip compared to the native lane allocation on the RIVE (there could also be some influence due to 6 cores over 4).
One 580
Similar to the one 7970 setup, using one GTX 580 has a split between AMD and Intel that is quite noticeable. Despite the split, all the CPUs perform within 1.3 FPS, meaning no big difference.
Two 580s
Moving to dual GTX 580s, and while the split gets bigger, processors like the i3-3225 are starting to lag behind. The difference between the best AMD and best Intel processor is only 2 FPS though, nothing to write home about.
DiRT 3 conclusion
Much like Metro 2033, DiRT 3 has a GPU barrier and until you hit that mark, the choice of CPU makes no real difference at all. In this case, at two-way 7970s, choosing a quad core Intel processor does the business over the FX-8350 by a noticeable gap that continues to grow as more GPUs are added, (assuming you want more than 120 FPS).
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Achaios - Friday, May 10, 2013 - link
@Ian Cutress: Hello Ian, please get a hold on a Quad Core Intel Core 2 CPU (q9540, q9550, q9650, qx9650, qx9770) and include it in your testing. I don't know where you get that "many people are still on Core 2 Duos" maybe you have seen some sort of market research? I still use a QX 9650 for gaming (WoW and SW:TOR-MMO's) and I am very happy with its performance. It would be nice to see how the high-end Core 2 CPUs measure up against modern CPUs.Andy_1 - Friday, May 10, 2013 - link
What a great Article, As I am in the process of making my mind up what to buy in the next two months this answers so many of my questions. Thank you! My main unanswered question some how seemed to get missed OR did I not read correctly??QThe results on the games show the 2 CPU config as scoring zero! is that because the wouldn't run the software on the rig or what?
ajlueke - Friday, May 10, 2013 - link
Great article. For those of us still gaming at 1080p with single GPU set ups, it is nice to know that it doesn't really matter if I spend a little less on the CPU and divert those funds toward a higher end GPU.Gamer4Life63 - Friday, May 10, 2013 - link
First, well done piece with lots of great info. Now then I would love to see this same kind of look done at 1080 resolutions with a mid range card like a 7870 or 7850. Would also love to see some other games added to the mix like a modern MMO or Skyrim that is a bit harder on the CPU.SurrenderMonkey - Friday, May 10, 2013 - link
Yes, Intel has great engineers not to forget the business gurus. Intel did a great job on Larrabee, choose(?) not to be in the Nextgen consoles and it will be jam tomorrow in the tablet and smartphone market. In April Intel reported a downturn of 25% in profits which it attributed to a decline on the PC market. As Anandtech has just shown the GPU is where the money is at, the CPU is a passenger and time to replace is extending. Intel makes good processors but it is also a one trick pony who has failed to move with the times.MarcVenice - Friday, May 10, 2013 - link
You thought of some many things to consider, yet when you say: We know what's missing, you forgot so many things. I didn't read all the comments so excuse me if someone already mentioned it. But what's missing is several games. Crysis 3 for example, or Far Cry 3.You mentioned that 1440p is a niche (it's 2560x1440 btw, 1440p isn't technically a resolution). So why didn't you test at 1920x1080, not only are games more prone to being cpu-limited, but games like Crysis 3 or Far Cry 3 are actually more demanding then games like DiRT 3.
Reason I mention this, is that I've found there to be a rather big difference between a X4 970 and a 3960X in those games, at ultra settings in Crysis 3 and FC3, with a GTX 660, 670 and 680. I know Anandtech doesn't report minimum's, but if you take the time to do as many runs as you did, you can scientifically establish that the minimum fps is also greatly affected by slower cpu's.
Reason I respond after not having done so in years, is that I found your suggestion to pare a 5600K with a high-end gpu to be disputable, and that's me being mild. Especially since you more or less went and said that 'other' websites or testing didn't do their testing properly.
OwnedKThxBye - Monday, May 13, 2013 - link
I agree 100% MarcVenice.The recommendation also doesn't take into consideration the upgrade path of the PC. If you were to follow this suggestion, the probability of having to do a full CPU and motherboard upgrade instead of just the GPU when you next need to upgrade is going to be significantly higher. Most people don't want to do a full system upgrade after 2-3 years because they are CPU limited on the new title they want to play. I say spend the extra $100-$150 on a better CPU and potentially make the PC last another two years.
lesherm - Friday, May 10, 2013 - link
Ian, this is real research and journalism. This kind of in-depth reporting on hardware is exactly what keeps me coming back to anandtech, year after year. Your efforts are appreciated!TheQweaker - Saturday, May 11, 2013 - link
I agree with this.-- The Qweaker.
Animebando - Friday, May 10, 2013 - link
I would love to see this kind of write-up that covers surround/eyefinity resolutions. I've been fairly impressed with how my 7950 handles games across three monitors, and I've been an nVidia fan for years.