SLI Setup and Testing Configuration
The idea of multi-GPU gaming is pretty simple on the surface. By adding another GPU into your gaming PC, the game and the driver are able to divide the workload of the game engine and send half of the work to one GPU and half to another, then combining that work on to your screen in the form of successive frames. This should make the average frame rate much higher, improve smoothness and just basically make the gaming experience better. However, implementation of multi-GPU technologies like NVIDIA SLI and AMD CrossFire are much more difficult than the simply explanation above. We have traveled many steps in this journey and while things have improved in several key areas, there is still plenty of work to be done in others.
As it turns out, support for GPUs beyond two seems to be one of those areas ready for improvement.
When the new NVIDIA GeForce GTX 980 launched last month my initial review of the product included performance results for GTX 980 cards running in a 2-Way SLI configuration, by far the most common derivative. As it happens though, another set of reference GeForce GTX 980 cards found there way to our office and of course we needed to explore the world of 3-Way and 4-Way SLI support and performance on the new Maxwell GPU.
The dirty secret for 3-Way and 4-Way SLI (and CrossFire for that matter) is that it just doesn't work as well or as smoothly as 2-Way configurations. Much more work is put into standard SLI setups as those are by far the most common and it doesn't help that optimizing for 3-4 GPUs is more complex. Some games will scale well, others will scale poorly; hell some even scale the other direction.
Let's see what the current state of high GPU count SLI is with the GeForce GTX 980 and whether or not you should consider purchasing more than one of these new flagship parts.
Quick Performance Comparison
Earlier this week, we posted a brief story that looked at the performance of Middle-earth: Shadow of Mordor on the latest GPUs from both NVIDIA and AMD. Last week also marked the release of the v1.11 patch for Sniper Elite 3 that introduced an integrated benchmark mode as well as support for AMD Mantle.
I decided that this was worth a quick look with the same line up of graphics cards that we used to test Shadow of Mordor. Let's see how the NVIDIA and AMD battle stacks up here.
For those unfamiliar with the Sniper Elite series, the focuses on the impact of an individual sniper on a particular conflict and Sniper Elite 3 doesn't change up that formula much. If you have ever seen video of a bullet slowly going through a body, allowing you to see the bones/muscle of the particular enemy being killed...you've probably been watching the Sniper Elite games.
Gore and such aside, the game is fun and combines sniper action with stealth and puzzles. It's worth a shot if you are the kind of gamer that likes to use the sniper rifles in other FPS titles.
But let's jump straight to performance. You'll notice that in this story we are not using our Frame Rating capture performance metrics. That is a direct result of wanting to compare Mantle to DX11 rendering paths - since we have no way to create an overlay for Mantle, we have resorted to using FRAPs and the integrated benchmark mode in Sniper Elite 3.
Our standard GPU test bed was used with a Core i7-3960X processor, an X79 motherboard, 16GB of DDR3 memory, and the latest drivers for both parties involved. That means we installed Catalyst 14.9 for AMD and 344.16 for NVIDIA. We'll be comparing the GeForce GTX 980 to the Radeon R9 290X, and the GTX 970 to the R9 290. We will also look at SLI/CrossFire scaling at the high end.
Subject: General Tech, Graphics Cards | September 24, 2014 - 06:41 AM | Scott Michaud
Tagged: sli, nvidia
SLI Bridges are thrown in with compatible motherboards and there is usually little reason to want anything else. They work. There is no performance advantage for getting a "better" one, unless it does not connect with your specific arrangement of two-to-four cards. Today, NVIDIA gives another reason: a soft, beautiful glow to match the green "GeForce GTX" on the cards themselves.
Mind you, this is not the first glowing SLI Bridge. EVGA even provided us with a few of their own for a giveaway last year.
NVIDIA has three models, depending on the layout of your cards. 3-way SLI will need to be arranged as a series of two-wide with no gaps, using the "3-Way SLI Bridge". 2-way configurations have the choice of two empty slots between the two-wide cards, or no gap; former would purchase the "2-Way Spaced SLI Bridge" and the later, the "2-Way SLI Bridge". They each require GeForce GTX 770 cards, or better, as well as a recent GeForce Experience (1.7+). Certain non-reference designs may be incompatible.
The SLI Bridges are available now. Both 2-Way bridges are $29.99 and the 3-Way is $39.99.
Subject: Graphics Cards | July 29, 2014 - 06:27 PM | Jeremy Hellstrom
Tagged: asus, gtx 780, R9 290X DC2 OC, sli, crossfire, STRIX GTX 780 OC 6GB, R9 290X
We have seen [H]ard|OCP test ASUS' STRIX GTX 780 OC 6GB and R9 290X DirectCU II before but this time they have been overclocked and paired up for a 4k showdown. For a chance NewEgg gives the price advantage to AMD, $589 versus $599 at the time of writing (with odd blips in prices on Amazon). The GTX 780 has been set to 1.2GHz and 6.6GHz while the 290X is 1.1GHz and 5.6GHz, keep in mind dual GPU setups may not reach the same frequencies as single cards. Read on for their conclusions and decide if you prefer to brag about a higher overclock or have better overall performance.
"We take the ASUS STRIX GTX 780 OC 6GB video card and run two in SLI and overclock both of these at 4K resolutions to find the ultimate gameplay performance with 6GB of VRAM. We will also compare these to two overclocked ASUS Radeon R9 290X DirectCU II CrossFire video cards for the ultimate VRAM performance showdown."
Here are some more Graphics Card articles from around the web:
- ASUS GTX 780 STRIX OC 6GB Review @ Hardware Canucks
- Gigabyte GeForce GTX 770 (GV-N770OC-2GD) vs. ASUS Matrix Platinum (R9280X-P-3GD5) Video Card Review @ Hardware Secrets
- Ice-cold Temperature Killa: Arctic Accelero Hybrid II-120 GPU Cooler Review @ Techgage
- Examining AMD’s Driver Progress Since Launch Drivers: R9 290X & HD 7970 @ eTeknix
- HIS Radeon R7 250X and 260X iCooler @ Funky Kit
- Sapphire Dual-X R9 280 3GB OC Video Card Review @ Legit Reviews
- AMD Radeon R9 280X Round-up @ Legion Hardware
- HIS R9 280 IceQ X2 OC 3GB GDDR5 Video Card Review @ Madshrimps
- Sapphire Radeon R9 290 Vapor-X 4 GB @ techPowerUp
Subject: Graphics Cards | July 4, 2014 - 05:40 PM | Jeremy Hellstrom
Tagged: STRIX GTX 780 OC 6GB, sli, crossfire, asus, 4k
Multiple monitor and 4k testing of the ASUS STRIX GTX 780 OC cards in SLI is not about the 52MHz out of box overclock but about the 12GB of VRAM that your system will have. Apart from an issue with BF4, [H]ard|OCP tested the STRIX against a pair of reference GTX 780s and HD 290X cards at resolutions of 5760x1200 and 3840x2160. The extra RAM made the STRIX shine in comparison to the reference card as not only was the performance better but [H] could raise many of the graphical settings but was not enough to push its performance past the 290X cards in Crossfire. One other takeaway from this review is that even 6GB of VRAM is not enough to run Watch_Dogs with Ultra textures at these resolutions.
"You’ve seen the new ASUS STRIX GTX 780 OC Edition 6GB DirectCU II video card, now let’s look at two of these in an SLI configuration! We will explore 4K and NV Surround performance with two ASUS STRIX video cards for the ultimate high-resolution experience and see if the extra memory helps this GPU make better strides at high resolutions."
Here are some more Graphics Card articles from around the web:
- ASUS GTX 780 Strix 6 GB @ techPowerUp
- MSI GTX 780 Gaming 6 GB @ techPowerUp
- HIS R7 260X iCooler 2GB GDDR5 Video Card Review @ Madshrimps
- XFX Radeon R9 290X Double Dissipation 4GB @ eTeknix
- PowerColor Devil 13 Dual Core R9 290X 8GB Review @ OCC
- PowerColor Devil 13 R9 290X Dual Core Review @ Hardware Canucks
- XFX R9 280 Black OC Edition @ Kitguru
- HIS Radeon R9 280 IceQ X² OC 3GB @ Benchmark Reviews
- ASUS R7 260X DirectCU II OC @ [H]ard|OCP
Subject: General Tech, Graphics Cards | February 7, 2014 - 08:54 AM | Scott Michaud
Tagged: sli, crossfire
I will not even call this a thinly-veiled rant. Linus admits it. To make a point, he assembled a $5000 PC running a pair of NVIDIA GeForce 780 Ti GPUs and another pair of AMD Radeon R9 290X graphics cards. While Bitcoin mining would likely utilize all four video cards well enough, games will not. Of course, he did not even mention the former application (thankfully).
Honestly, he's right. One of the reasons why I am excited about OpenCL (and its WebCL companion) is that it simply does not care about devices. Your host code manages the application but, when the jobs get dirty, it enlists help from an available accelerator by telling it to perform a kernel (think of it like function) and share the resulting chunk of memory.
This can be an AMD GPU. This can be an NVIDIA GPU. This can be an x86 CPU. This can be an FPGA. If the host has multiple, independent tasks, it can be several of the above (and in any combination). OpenCL really does not care.
Obviously, to be fair, AMD is very receptive to open platforms. NVIDIA is less-so, and they are honest about that, but they conform to standards when it benefits their users more than their proprietary ones. I know that point can be taken multiple ways, and several will be hotly debated, but I really cannot find the words to properly narrow it.
Despite the fragmentation in features, there is one thing to be proud of as a PC gamer. You may have different experiences depending on the components you purchase.
But, at least you will always have an experience.
Summary of Events
In January of 2013 I revealed a new testing methodology for graphics cards that I dubbed Frame Rating. At the time I was only able to talk about the process, using capture hardware to record the output directly from the DVI connections on graphics cards, but over the course of a few months started to release data and information using this technology. I followed up the story in January with a collection of videos that displayed some of the capture video and what kind of performance issues and anomalies we were able to easily find.
My first full test results were published in February to quite a bit of stir and then finally in late March released Frame Rating Dissected: Full Details on Capture-based Graphics Performance Testing which dramatically changed the way graphics cards and gaming performance was discussed and evaluated forever.
Our testing proved that AMD CrossFire was not improving gaming experiences in the same way that NVIDIA SLI was. Also, we showed that other testing tools like FRAPS were inadequate in showcasing this problem. If you are at all unfamiliar with this testing process or the results it showed, please check out the Frame Rating Dissected story above.
At the time, we tested 5760x1080 resolution using AMD Eyefinity and NVIDIA Surround but found there were too many issues and problems with our scripts and the results they were presenting to give reasonably assured performance metrics. Running AMD + Eyefinity was obviously causing some problems but I wasn’t quite able to pinpoint what they were and how severe it might have been. Instead I posted graphs like this:
We were able to show NVIDIA GTX 680 performance and scaling in SLI at 5760x1080 but we only were giving results for the Radeon HD 7970 GHz Edition in a single GPU configuration.
Since those stories were released, AMD has been very active. At first they were hesitant to believe our results and called into question our processes and the ability for gamers to really see the frame rate issues we were describing. However, after months of work and pressure from quite a few press outlets, AMD released a 13.8 beta driver that offered a Frame Pacing option in the 3D controls that enables the ability to evenly space out frames in multi-GPU configurations producing a smoother gaming experience.
The results were great! The new AMD driver produced very consistent frame times and put CrossFire on a similar playing field to NVIDIA’s SLI technology. There were limitation though: the driver only fixed DX10/11 games and only addressed resolutions of 2560x1440 and below.
But the story won’t end there. CrossFire and Eyefinity are still very important in a lot of gamers minds and with the constant price drops in 1920x1080 panels, more and more gamers are taking (or thinking of taking) the plunge to the world of Eyefinity and Surround. As it turns out though, there are some more problems and complications with Eyefinity and high-resolution gaming (multi-head 4K) that are cropping up and deserve discussion.
Subject: Graphics Cards | August 14, 2013 - 10:03 PM | Ryan Shrout
Tagged: sweepstakes, sli, nvidia, giveaway, evga, contest
UPDATE: Winners have been selected and contacted - if you weren't one of the five winners check back for more contests and giveaways!! Thanks for listening!!
While at Quakecon this year EVGA showed off its new collection of Pro SLI Bridges that add a bit of sexy to any NVIDIA multi-GPU system. These are much more than just the standard SLI bridge that you know of today: they are sleek, have a brushed metal finish and if you have GTX 700-series or TITAN graphics card, they light up as well!
Because EVGA is a big supporter of PC Perpsective, they are sending over a handful of the 3-Way Pro SLI Bridges (that can also be used in 2-Way configurations) to give away to our readers.
How can you win one of the five free units that EVGA sent us?
- Fill out the form below with the requested information.
Listen to this week's (Episode #264) PC Perspective Podcast (live or after the fact) and I'll give you the code word to include in the form below.
- You can download or watch the podcast right here: http://pcper.com/podcast
That's it!! You can win anywhere in the world and our winners will be randomly picked from the submissions we receive no later than the 20th of August at 6pm ET.
A big thanks goes to EVGA for providing these units!!
Subject: General Tech | August 8, 2013 - 06:22 PM | Ken Addison
Tagged: podcast, video, amd, nvidia, crossfire, sli, frame rating, 7990, john carmack, Oculus
PC Perspective Podcast #263 - 08/08/2013
Join us this week as we discuss AMDs Crossfire Fix, Carmack Leaving id, Left 4 Dead 3 rumors and more!
The URL for the podcast is: http://pcper.com/podcast - Share with your friends!
- iTunes - Subscribe to the podcast directly through the Store
- RSS - Subscribe through your regular RSS reader
- MP3 - Direct download link to the MP3 file
Hosts: Ryan Shrout, Jeremy Hellstrom, Josh Walrath, and Allyn Malventano
Program length: 1:13:47
Introduction and Design
While Lenovo hasn’t historically been known for its gaming PCs, it’s poised to make quite a splash with the latest entry in its IdeaPad line. Owing little to the company’s business-oriented roots, the Y500 aims to be all power—moreso than any other laptop from the manufacturer to date—tactfully squeezed into a price tag that would normally be unattainable given the promised performance. But can it succeed?
Our Y500 review unit can be had for $1,249 at Newegg and other retailers, or for as low as $1,180 at Best Buy. Lenovo also sells customizable models, though the price is generally higher. Here’s the full list of specifications:
The configurations offered by Lenovo range in price fairly widely, from as low as $849 for a model sporting 8 GB of RAM with a single GT 650M with 2 GB GDDR5. The best value is certainly this configuration that we received, however.
What’s so special about it? Well, apart from the obvious (powerful quad-core CPU and 16 GB RAM), this laptop actually includes two NVIDIA GeForce GT 650M GPUs (both with 2 GB GDDR5) configured in SLI. Seeing as it’s just a 15.6-inch model, how does it manage to do that? By way of a clever compromise: the exchange of the usual optical drive for an Ultrabay, something normally only seen in Lenovo’s ThinkPad line of laptops. So I guess the Y500 does owe a little bit of its success to its business-grade brethren after all.
In our review unit (and in the particular configuration noted above), this Ultrabay comes prepopulated with the second GT 650M, equipped with its own heatsink/fan and all. The addition of this GPU effectively launches the Y500 into high-end gaming laptop territory—at least on the spec sheet. Other options for the Ultrabay also exist (sold separately), including a DVD burner and a second hard drive. The bay is easily removable via a switch on the back of the PC (see below).