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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iamezza - Thursday, May 9, 2013 - link
I have 3 x 1080p and a 7970, on modern games it isn't possible to get 60fps without turning settings way down. Really need 2 x 7970 to maintain 60+ fpsTheInternal - Saturday, May 11, 2013 - link
I'm guessing it does 30+ FPS comfortably though?Arnulf - Wednesday, May 8, 2013 - link
Are you retarded or just an imbecile ?marc1000 - Wednesday, May 8, 2013 - link
good work Ian!that's a LOT of data, but the best part is the explanation of WHY. hope it makes matters clear.
side note: it was nice to see the link to www.adrenaline.com.br ! those guys are insane indeed! =D
Doomtomb - Wednesday, May 8, 2013 - link
I have an i7-875K. I would like you to include an i7 from the Westmere/Nehalem generation. Thanks!mapesdhs - Monday, May 20, 2013 - link
I'm doing lots of tests that should help in your case. If you want me to test anything specific,
feel free to PM. I have the same 875K, but also 2500K, 2700K, 3930K, Ph2 965, QX9650
and many others.
Ian.
Pheesh - Wednesday, May 8, 2013 - link
I'm really surprised that minimum FPS wasn't also tested. Testing just for average FPS is not that informative to the actual experience you will have. If given the choice between two CPU's I'd take one averaging 70 fps but with a minimum fps of 50 over one that averages 80fps but has a minimum fps of 30.mip1983 - Wednesday, May 8, 2013 - link
Perhaps some games are more CPU limited, I'm thinking MMO's like Planetside 2 were there are a lot of players at once. Not sure how you'd benchmark that game though.bebimbap - Wednesday, May 8, 2013 - link
Ian I know you are a BL2 fan. The game is written with a old UT engine i'm told, so it's performance scaling isn't the same as some of these other titles. The method of testing you used was similar to how I buy my own equipment and recommend to others.With my same 3770k clocked at stock 3.9ghz I can only get about 57fps with my gtx670. when it is OC'd to 4.7ghz that same scene now becomes GPU limited at 127fps on my 144hz lcd. I'm glad you posted this. When people ask for my advice on what hardware to buy, I always tell them, that they should aim for a resolution first, 1080p for example, then what game they would want to play and what performance presets, mid settings 120hz, then buy a gpu/cpu combo that compliments those settings. if your budget allows then up the hardware a tier or two. Too many times do I see people just buy a top tier GPU and wonder why their fps is lower than expected. My way your expectations are met, then if budget allows, are exceeded. I hope you start a trend with this report. So that others can go this route when performing upgrades.
Michaelangel007 - Wednesday, May 8, 2013 - link
The article is a good start! Pity it didn't include the Tomb Raider benchmark that anyone can run, nor include a discussion about the badly implemented Windows timer frequency that Lucas Hale documented with his "TimerResolution" program. HyperMatrix found lowering the default timer resolution from 10ms down to 1 ms allowed for "Crysis 3 - 30% Framerate and Performance"