SLI Guide: How to enable SLI, check if SLI is enabled, actually working in your game and what to do if it's not

[Glzmo]

SLI Guide
How to enable SLI, check if SLI is enabled, actually working in your game and what to do if it's not
by Glzmo

Since there has been confusion about how to enable SLI, how to check if it works on the system and in individual applications/games, etc. I thought I'd write up a little guide for it, which will hopefully allow everyone to get SLI working on their Alienware laptop and their favorite game.
For SLI to work, you'll require a computer with at least two compatible, SLI capable Nvidia video cards linked with an SLI cable and the latest Nvidia drivers. On some systems, (Hybrid-) SLI/Graphics will also have to be enabled in the BIOS or Integrated Graphics disabled. Owners of select Alienware systems will also have to make sure that they are not in the power saving mode called "Stealth mode" for SLI to work.

I. Check if SLI is enabled and working in your game(s)
The first thing you'll want to do is to check if SLI is enabled properly and running in your 3D Application/Game. To do this, follow the following steps:
1. Make sure you have SLI enabled, by going to the Nvidia control panel by right clicking on the Desktop and slecting NVIDIA Control Panel.
If you don't have the Nvidia control panel installed, you are likely using drivers provided by Windows Update. In this case, skip forward to Section II.A. of this guide to install the latest drivers.
2. In the Nvidia Control Panel, click on Set SLI and PhysX configuration in the Task menu on the left side.
3. Make sure the radial button next to Enable SLI (recommended) is marked. If not, mark it, click Apply and follow the on-screen instructions.
4. When that's in Order, click on Adjust image settings with preview. Make sure Use the advanced 3D image settings is marked. If not, mark it and click Apply.
5. When that's in Order, click on Manage 3D Settings in the task menu on the left.
6. On the right side, look for an entry called SLI Performance Mode. Make sure this is set to NVIDIA recommended.
7. To check whether SLI is working in your game or not, go to the 3D Settings in the horizontal menu bar (not Manage 3D Settings in the task menu!) and make sure Show SLI Visual Indicators has a checkmark next to it. This will enable the SLI visual indicator in 3D Applications like games, which will show up as a green bar on the left side/middle of the screen and SLi written next to it if SLI is working in a 3D Application/game.
8. Close the Nvidia Control Panel.
9. Start the 3D Application/game you wish to check SLI on. If the green SLI visual indicator overlay appears on screen that says SLI, SLI is working in your game and all is good. If no indicator appears, it's not working (unless it's the PhysX indicator that comes with newer PhysX revisions, but that one says PhysX > GPU or PhysX > CPU).
10. If it's not working, try some other games/3D Applications and see if the SLI visual indicator shows up there. If it does, your driver likely doesn't include a proper SLI profile for the game you've tried before yet. In this case, move on to section II. of this guide.


II. Add/Update an SLI Profile for your game
This section describes how to update your Nvidia driver's SLI profile to support your game. There are several ways to do this, one is by updating the drivers to the latest version, another with the latest Nvidia SLI Profile Update, using the nHancer Nvidia profiling Utility or a combination of the aforementioned. These will be described in the folloing subsections.

II.A. Update your Nvidia driver to the latest version
SLI support is provided to games via Nvidia Driver profiles. The newer your game, the more likely it is that there is no profile included in older drivers. Therefore you should update your video card drivers to the latest version.
Warning: Not all Nvidia drivers are fully compatible with all hardware. This is often the case especially with various Notebook video card combinations, especially ones that feature Hybrid SLI. These usually need special drivers to work correctly. These are usually based on older driver versions. Make sure to install the proper drivers for your hardware. If you don't feel comfortable with updating your video card drivers or don't wish to update your driver to the latest version for whatever other reason, skip on to section II.B. and/or II.C. of this guide to get a working SLI profile for your application/game added to your current Nvidia video card driver.
Otherwise, continue with the following steps:
1. Download the latest Nvidia driver for your video card (in case the official Nvidia drivers don't work properly with your video card/system, download the drivers from your hardware manufacturer or give the modified drivers over at LaptopVideo2Go a try).
2. Install the driver.
3. Follow the Instructions from section I. of this guide.
4. If it didn't help, continue with section II.B..


II.B. Nvidia SLI Profile Update
Nvidia has been providing periodical SLI Profile Updates when new games have been released for a while now. These updates add SLI profiles for many newer games to older drivers, which should allow these games to fully utilize SLI.
1. If your new driver doesn't feature a proper SLI profile for the game, you will need to add/Update a SLI profile.
You can Nvidia.com's driver page.
2. Scroll down if needed and click on Nvidia SLI Profile Updates.
3. Check if the game you need SLI support for is mentioned in the Release Highlights of the SLI Update.
4. Download and Install the latest SLI Update.
3. Follow the Instructions from section I. of this guide.
4. If it didn't help, continue with section II.C..


II.C. Create a custom SLI Profile using nHancer
nHancer is an advanced profiling utility for Nvidia video cards. It allows you to tweak many (often hidden) Nvidia driver features which can't be done with the Nvidia control panel on a game-to-game basis, including setting SLI compatibility, getting Anti-Aliasing to work in games that don't normally support it with compatibility flags and much more. It will also allow you to see all driver profiles that are available for your games and which settings they are set at.
1. Download and install the Nvidia driver profiling utility nHancer from http://nhancer.com.
2. Go to the nHancer Forum and check if somebody has posted a SLI profile for your game and/or enter something like [game name] nHancer SLI profile in your favorite web search engine.
3. If you find a profile, download it and double-click on it or open nHancer, click on Profile->Import and select the profile you have just downloaded.
4. Make sure to check override settings.
5. If you couldn't find a proper profile online, you will have to create one yourself.
2. Start nHancer.
3. Once it's done, enter the Application/game name in the dropdown box to see if there is a driver profile for it in existence.
4. If it is, proceed with step 10..
5. If it isn't, click on the Create a new profile Button.
6. Enter the name of the game/application for the profile.
8. Next to the Executables field, click on Add an executable to the profile(...).
9. Browse the folder you have installed your game in and select the game's .exe file.
10. Click on the profile for your game.
11. On the right hand side, click on the SLI Mode tab (if it's a DirectX9 game) or SLI DX10 tab (if it's a DirectX10 game).
12. Tick the checkbox marked SLI Mode (or SLI DirectX10 Mode for a DirectX10 game).
13. Experiment with the various options in the dropdown menu and the checkboxes in the Compatibility flags tab. It's a trial and error at this point, start the game and see how your settings affect it. It's generally wise to check which game engine a game uses and
14. I won't go into more detail about creating and tweaking profiles via nHancer here. If you have any questions or need further advice or assistance, I suggest to visit nHancer.com, sign up to the nHancer Forum and ask for help there.


I hope this guide will help the SLI users out there to enable SLI on their system and their favorite game(s).

[Glzmo]

Addendum: Quick Links used in the Guide

Nvidia Driver Page
Download Nvidia Drivers and Nvidia SLI Profile Updates.

LaptopVideo2Go Nvision Forums
You can find various drivers here, modified to work with a white variety of Hardware that isn't supported by the original drivers.

nHancer
Download the Nvidia Profiling Utility nHancer, which allows you to create and tweak driver profiles to enable SLI, FSAA, Anisotropic Filtering and much, much more for your individual games. The ultimate tool for every owner of Nvidia video cards.

nHancer Support Forum
Get help, information, profiles and more related to nHancer.


This Guide is a work in progress. I'll update it as I see fit.

Feel free to link it in various threads, including stickies for Alienware systems that support SLI.

[ThaDutchy]

Maybe you have to add a Cross-fire note/section, now that ATI is in the "game" aswell.
I'm not sure if there are any known problems allready. Nice work though! +rep.

[Trelawney]

Thanks Glzmo

Excellent summary and a topic asked very often as well!

Appreciate the time some folks take to do do summaries like this, but just wish more people would be a little more grateful sometimes!

Good work!

Cheers

Trelawney

[Glzmo]

Originally Posted by ThaDutchy

Maybe you have to add a Cross-fire note/section, now that ATI is in the "game" aswell.

I would, if I had any AMD/ATi crossfire video cards. I haven't used Crossfire in many years. Without recent first hand experience, I don't feel I'm in a position to write up a guide for it.

The only thing I know is that AMD/ATi drivers have the driver profiles coded into the driver, unlike Nvidia, who uses an easily accessible .xml file. AMD/ATI users therefore can't create Crossfire profiles themselves, nor is a utility like nHancer possible. They are therefore still at the mercy of getting an updated driver or official driver patch to get Crossfire (and FSAA) to work properly with new games, or have to try to rename the game's executable files to one of a game that's supported in the driver and uses the same compatibility flags, which of course isn't possible for all games, especially those utilizing launchers (various MMORPGs, etc.). Also, I don't believe there is an easy way to check if Crossfire is actually working and active in a game/application unlike the SLI Visual indicator (but I may be well out of the loop here).

Anyway, if anyone was to write up a similar guide for Crossfire, I'd gladly link it to send AMD/ATi users there.

[Glzmo]

Added a couple of steps to the main post.

[SillyHoney]

Thank you! To finish a thread like this is very time consuming

[The_Moo™]

great job .... glad to see after a while we are finally getting some members that will contribute back

[gatty]

I have recieved a m17x as a replacement for a faulty m1730, system is great apart from the following issue.

When I boot the system it uses the intergrated graphics. Device manager shows ONLY the 9400.

When I open the NVIDIA control panel there is no option at all for SLI.

I reboot, head into BIOS and disable the intergrated graphics. System boots and SLI is active. Device manager shows the 2 cards, also NVIDIA control panel now displays both cards and the settings.

If I reboot the system the intergrated card becomes active again and no more SLI, am I missing somehting?

[Glzmo]

Originally Posted by gatty

I have recieved a m17x as a replacement for a faulty m1730, system is great apart from the following issue.

When I boot the system it uses the intergrated graphics. Device manager shows ONLY the 9400.

When I open the NVIDIA control panel there is no option at all for SLI.

I reboot, head into BIOS and disable the intergrated graphics. System boots and SLI is active. Device manager shows the 2 cards, also NVIDIA control panel now displays both cards and the settings.

If I reboot the system the intergrated card becomes active again and no more SLI, am I missing somehting?

To enable SLI on the M17x, you'll either have to have Hybrid Graphics Enabled in BIOS or have Hybrid Graphics disabled and the integrated graphics disabled as well (otherwise it will run only with the integrated 9400M G).
With the M17x, when you boot it from battery (without the Power Adapter plugged in), the BIOS will disable the dedicated video card(s) and only enable integrated graphics (it's a shame this is forced behaviour and can't be turned off in the BIOS). Even when you plug the power adapter back in later, it won't automatically switch the So if you want to use SLI, you'll have to boot your system with the power adapter plugged in, or change it in the BIOS when prompted to when booting from battery.
You can also switch which video cards are being used by pressing FN+F7 within Windows (if Hybrid Graphics is enabled in the BIOS and the drivers are installed correctly, this will allow you to switch between integrated graphics and your SLI cards on the fly without rebooting, if it's disabled, it will prompt you to reboot and automatically switch the BIOS setting for you while rebooting).