- Graphics Cards
- Headphones & Headsets
- Keyboards & Mice
- Sound Cards
- RAIDR Express SSD
- Why ROG?
- ROG PRO
- About ROG
Our guide below covers those interested in setting up Nvidia SLI or AMD CrossFireX on an Intel Z77 motherboard such as the ROG Maximus V series (we’ve used the Maximus V Formula), equipped with a 3rd Generation Intel Core CPU with PCI-Express Gen 3.0 capable CPU (such as the Core i5-3570K or Core i7-3770K).
Installing the first graphics card
- The Maximus V Formula has three full size (16x) PCI-Express slots, colored in red
- The two we are interested in for 2-way multi-GPU is the top slot and middle slot. Using just the top (primary) slot will give the graphics card PCI-E 3.0 16x bandwidth, while using both slots splits the lanes such that both have PCI-E 8x. Despite losing half the potential bandwidth per card, the PCI-E 3.0 standard provides more than enough data throughput, leaving your graphics card performance unaffected.
- Ensure each card fits securely, with the retention clip popping into place and that you connect the necessary PCI-E 6/8pin power connectors to the graphics card.
Installing the second graphics card
- When selecting a second GPU, you should ensure it’s as similar as possible to the primary GPU. For Nvidia cards, you must match the same GPU; so a GTX 670 with a second GTX 670. The driver will synchronize clock speeds if the two cards run at different frequencies. With AMD cards there is more lee-way; you can, for example, match an HD 7950 with an HD 7970, although for optimal performance scaling it’s again better to match both cards like for like.
- It might be obvious, but it’s worth saying you can’t mix Nvidia with AMD GPUs and you cannot mix two different generations of product: a GTX 500 series won’t SLI with a GTX 600 series for example.
- Fitting a second graphics card to the Maximus V Formula is easy; just slot it into place in the second (middle) PCI-E 3.0 slot. The board is laid out to allow a clear gap between the top and bottom GPU even if you’re using a graphics card with a triple slot cooler, such as some ASUS DirectCU II models.
- While the added space between the two cards might seem helpful for cooling, DO NOT fit the second card into the third (lowest) PCI-E slot. This will result in the top slot with 8x lanes of bandwidth, however the bottom slot only offers 4x bandwidth, limiting performance.
- With both graphics cards fitted and powered, it’s time to fit the SLI or CrossFire bridge cable (depending on whether you’re using Nvidia or AMD GPUs respectively). On both AMD and Nvidia graphics cards you can plug in the cable to either set of pins, with the cable aligning in a straight line from top to bottom. The SLI and CrossFire connectors do not match, so you can’t accidentally fit the wrong bridge.
CrossFire cables are provided in AMD graphics card boxes, whereas SLI cables are provided with the motherboard instead.
The SLI/CrossfireX Bridge
Just pop on the bridge between the two cards as follows. Both will require just one connector. The second connector is used when more than two cards are added in 3-way and 4-way multi-GPU.
Connect your displays
If you’re using a single display, connect it to the output of the top-most card. However, be advised that certain outputs will be disabled when using multi-GPU setups; refer to Nvidia or AMD’s requirements pages to make sure your setup will work. If you plan to use three monitors, be aware that AMD requires you to connect the third monitor via DisplayPort, whereas Nvidia’s model favors three DVI connections.
For Nvidia configurations, refer to this guide.
With the cards fitted into the right slots, powered up and connected via the required SLI/CrossFire bridge, there’s still a couple of things left to check.
Head into the Maximus V Formula’s UEFI BIOS – you should be in Advanced Mode by default. Navigate to the Advanced tab, and select System Agent Configuration, followed by the NB PCIe Configuration. You should see a screen which matches that below, with both the top PCI-E slots running at 8x. You can force these slots to use PCI-E 3.0 (Gen 3) here if you wish, as this can sometimes improve stability.
Install the driver
With the hardware in place, it’s time to head into Windows and install the latest Nvidia or AMD driver. You may want to grab the latest beta driver, as these will often have the most recent SLI or CrossFire profiles included.
SLI – SLI should automatically enable if the setup is correct. You can double check this though by entering the Nvidia Control panel and selecting the Configure SLi, Surround, PhysX tab. Here you can check that SLI is enabled, adjust Nvidia Surround if you’re using multiple monitors, or assign one of the GPUs as a PhysX processor.
CrossFire – CrossFire should also automatically enable once the driver has been installed. To double check it, open the Catalyst Control Center, select the Gaming tab and select AMD CrossFire. Here you can enable, or disable CrossFire. Also noteworthy is that if you’re using a 7-series AMD GPU, don’t be alarmed if your second GPU’s fan switches off when idle. This is part of AMD’s ZeroCore power technology; the card will power back up when needed.
A word on performance scaling
Doubling up on graphics power does not always grant matching improvements, as there’s a significant reliance on the driver. However, as you can see from our example benchmarks in Unigine Heaven 3.0, given the right circumstances you can expect huge gains even at lower resolutions.
Below are some Unigen Heaven 3.0 benchmarks run at 1920 x 1080 for both 1x (left) and 2x (right) Geforce GTX 670:
And for and 1x (left) and 2x (right) Radeon HD 7970. It’s not exactly twice the performance, but at around 90% increase is pretty accurate for most multi-GPU setups now.
Switching to use a multi-GPU setup does not always guarantee a significant performance increase inevery game. Certain titles will offer better and worse multi-GPU scaling, and new releases will likely require a driver or SLI/CrossFire profile update to ensure optimum performance. If you encounter such issues, you should refer to Nvidia’s or AMD’s latest drivers – even beta (pre-official release) drivers – which typically receive multi-GPU updates before the WHQL drivers which have to be certified by Microsoft.
Power Supply Note:
Adding a second graphics card will also dramatically increase your PC’s power consumption in 3D gaming; ensure you have a PSU that’s up to the task. For a dual-GPU setup as detailed here, we’d recommend no less than a 700W PSU.
Did you follow our guide, how did you get on? Let us know in the forums.
▼ Related Articles
Video: ARES II CrossfireX Review
( Relevance » 9.1 )
Gallery: RAIDR Express SSD
( Relevance » 13.4 )
Gallery: ARES II
( Relevance » 13.1 )
ASUS Unveils ARES II Graphics Card and ROG RAIDR Express SSD
( Relevance » 9.3 )
Learn How To PC DIY
You've got the hardware, now crank it to the max! Check out our full coverage of PC build, overclocking, and feature guides.
FIND US ON FACEBOOK
What makes ROG kit so special? Discover its unique innovations and exclusive technologies.
ROG Forum Hot Threads
Winter Wonderland 2013
- Winter Wonderland 2013
10:27:05 3 Dec, 2013 · 101 replie(s)
- 3770k temps at 4.8ghz
20:37:44 28 Nov, 2013 · 97 replie(s)
- Random freezing and glitching
16:09:10 29 Nov, 2013 · 87 replie(s)
- What is LINUX?
17:36:03 11 Nov, 2013 · 80 replie(s)
- Addicted to Hardware more than gaming?
05:18:15 26 Nov, 2013 · 78 replie(s)
- BSOD "0x0000000a Hero
20:16:26 26 Nov, 2013 · 65 replie(s)
- New Black Edition worked for about ...
15:02:26 29 Nov, 2013 · 62 replie(s)
- Maximus Formula VI Bios 1002 - now ...
17:39:25 18 Nov, 2013 · 47 replie(s)
- What are best graphics cards for 2-...
18:21:58 27 Nov, 2013 · 45 replie(s)
- My god, it's done. No going back...
00:35:26 30 Nov, 2013 · 44 replie(s)
- Broken seal
18:33:44 14 Nov, 2013 · 43 replie(s)
- Nvidia GeForce 331.82 WHQL Driver
11:08:33 19 Nov, 2013 · 38 replie(s)
- Asus Maximus VI Hero Issue - Need a...
11:36:32 28 Nov, 2013 · 38 replie(s)
- Arne's Linux adventure
12:04:04 30 Nov, 2013 · 37 replie(s)
- ASUS ROG is not always what it looks
13:45:41 11 Nov, 2013 · 32 replie(s)
- ASUS-Z87-A problem with sound. Help...
16:26:44 23 Nov, 2013 · 31 replie(s)
- Anyone Have a Look? (Vbios, Overclo...
02:59:45 30 Nov, 2013 · 31 replie(s)
- Christmas Season STEAM giveaway!
18:23:10 28 Nov, 2013 · 30 replie(s)
- Help please, New Build.. MAX VI GEN...
05:13:39 23 Nov, 2013 · 28 replie(s)
- Company Of Heroes STEAM Giveaway
22:35:14 18 Nov, 2013 · 27 replie(s)
It is that time of the year when folks in the Northern Hemisphere a...By HiVizMan, in "Team ROG & Competitive OC Discussion"3770k temps at 4.8ghz
hello guys i have a custom watercooled pc with 360 mm rad and 28...By Braindamage, in "General Hardware, Overclocking & Tweaking"Random freezing and glitching
CORSAIR Dominator Platinum 16GB (2 x 8GB) 240-Pin DDR3 SDRAM DDR3 2...By Korvan, in "General Hardware, Overclocking & Tweaking"What is LINUX?
I know I probably sound lame, but could someone please explain to m...By TotalONE, in "ASUS Software, Windows, Linux or SteamBox"Addicted to Hardware more than gaming?
Whats up y'all. Just curious if anybody here gets overwhelmed with ...By John Smith, in "PC Gaming"BSOD "0x0000000a Hero
Hello guys! New to the forum :) I have the same problem and it dri...By septerra, in "Maximus VI Series Motherboards"New Black Edition worked for about 20 mins
4930k 2 titans rampage iv black 900d dominator plat ax1200i ...By BeeF_DriPPings, in "Rampage Series Motherboards"Maximus Formula VI Bios 1002 - now missing from asus update site??
So this weekend i went to support on asus and downloaded the latest...By mcurtis, in "Maximus VI Series Motherboards"What are best graphics cards for 2-WaySLi/Crossfire under 650$ (in total)?
Well, most of you would have already seen my post asking about my b...By Hyper Droid, in "Build Advice"My god, it's done. No going back...
That's it guys, I've done it, there's no going back.... What am ...By Hyper Droid, in "PC Gaming"Broken seal
Hello guys I have just bought a new evga 780 hydro cooper classi...By Braindamage, in "General Hardware, Overclocking & Tweaking"Nvidia GeForce 331.82 WHQL Driver
Havent installed and tried them yet. But here's the new WHQL fo...By Krebb, in "G750 Series Notebooks"Asus Maximus VI Hero Issue - Need advice dont know what to do
Hello all, I completed a new comp build with the following compo...By RickH89, in "General Hardware, Overclocking & Tweaking"Arne's Linux adventure
So, have Ubuntu "up and running" on my RIG...like the look so far. ...By Arne Saknussemm, in "ASUS Software, Windows, Linux or SteamBox"ASUS ROG is not always what it looks
I am a regular user of computer products, I am also engaged as a co...By Aurvangir, in "G750 Series Notebooks"ASUS-Z87-A problem with sound. Help required.
Hello guys, today i got my new hardware, i got this motherboard Asu...By Madnix, in "TUF and ASUS Motherboards [Intel]"Anyone Have a Look? (Vbios, Overclock) 765, 770 and 780m
Hi guys, just dropping by to show you guys a link I stumbled upon e...By abeepak1, in "G750 Series Notebooks"Christmas Season STEAM giveaway!
[B][COLOR="#B22222"]Hi ROGers![/COLOR][/B] Time for my second [B]S...By EnthusiastBuild, in "PC Gaming"Help please, New Build.. MAX VI GENE.. Power cycling..
Hello.. When I power it up... I see the Q-Code go to b6 and then I ...By Apex2Apex, in "Maximus VI Series Motherboards"Company Of Heroes STEAM Giveaway
Hi! Since i really like this forum and its awesome community a lot...By EnthusiastBuild, in "PC Gaming"
- Winter Wonderland 2013
- Could not connect to Twitter
Article TagsAMD asus cheap games Competition Crosshair V Formula-Z DirectCU II eSports event Extreme Overclocking Gallery gaming GeForce GPU Tweak graphics card guide HD 7970 Intel LN2 Maximus V Extreme Maximus V Formula Maximus V GENE Maximus VI Extreme Modding motherboard NVIDIA Overclocked overclocking overview PC PC gaming PC Mod PC modding PC Mods Pictures PR Rampage IV Extreme review rog Super Alloy Power TOP unboxing video watercooling World Record YouTube