Date:
Wednesday, March 23, 2005
Author:
Brent Justice
Editor:
Kyle Bennett
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NVIDIA SLI Support - Getting Better

A new driver from NVIDIA has improved SLI support and brought new features to the table. Inside we not only test this latest driver, focusing on SLI support and performance, but we also comment on what we would like to see in future iterations of NVIDIA’s SLI.

Grammatical & Spelling Editor: Timothy Daniel

Introduction:

A couple of months ago we wrote an editorial exposing some real truths about the current implementation of NVIDIA’s SLI that may not have been readily apparent. We highly suggest you read that editorial first as this one is an update to it.

Our main concern about the way NVIDIA’s SLI works stems from the fact that it is a game-by-game process. What this means is that the driver requires a profile to be programmed into it that states whether a certain game is going to run in SLI. Furthermore, the profile must also be programmed to use either Alternate Frame Rendering (AFR) or Split Frame Rendering (SFR). When a game is run, the driver looks to see if there is a profile associated with the .exe and then it implements whatever set SLI mode is in the driver. If there is no profile set in the driver for a particular game specifying the SLI mode, then you will not get the performance benefit of SLI in that game.

Obviously, this has huge implications for new games that do not have a driver profile. This means that NVIDIA has to examine every game and find the best method of SLI to use, and then program a profile into the driver. Therefore, NVIDIA must now not only be concerned with improving performance and stability under normal circumstances, but they also must examine new games and program SLI profiles for them. The extra development time required for SLI implementation gives us concern about the frequency at which NVIDIA releases drivers. Recently, perhaps partially due to the extra development time required to implement SLI, there has sometimes been many months between new official WHQL driver releases on NVIDIA’s website. Since there are long periods of time between new driver releases, we often have situations where new games are released without an SLI profile. Furthermore, depending on when the game is released relative to a new NVIDIA driver release, games can sometimes remain without an SLI profile for months at a time. What do you do? Do you play the game you just bought in single-GPU mode even though you have two video cards? Do you wait until NVIDIA releases a new driver so that you can play it with the performance benefit of SLI?

ForceWare Release 70 Series

Luckily, NVIDIA has stepped up to the plate in responding to these concerns. Up on NVIDIA.com now is a new driver release, ForceWare 71.84. This driver is WHQL certified and was released on March 11th, 2005. For comparison, the previous driver version, ForceWare 66.93, was released on November 9th, 2004. Therefore, it has been approximately four months since a new driver release, and, as you can imagine, many new games have been released between those four months.

More SLI Support and Features

This new driver is the first in the new Release 70 series. The Release 70 series drivers are bringing with them some much-needed SLI features, bug fixes, and performance improvements.

This new NVIDIA ForceWare Release 70 graphics driver will boost performance of NVIDIA graphics processing units (GPUs) in single and multi GPU configurations significantly. It increases the number of games that have SLI profile to over 70.

Indeed, NVIDIA now has support for over 70 games as you can see right here. In our first article here, we had a table at the bottom of the page that showed "No SLI Performance Benefit" for seven out of the twelve games we tested. If you look on the new list of games supporting SLI, you will find that Flight Sim 2004 is the only game on our table that is not on NVIDIA’s new list. This is good news as we are finally seeing much more support for SLI.

Ability to add SLI profiles

NVIDIA has also included in this new driver the ability to edit and add SLI profiles, which can be activated with Coolbits.

New in ForceWare Beta Version 71.84, you can easily create a new SLI Application profile or modify an existing one by using Coolbits. In addition, two new rendering modes are now available: Auto-select and Alternate Frame Rendering 2.

There is a new page up on NZone that goes into great detail on editing and creating SLI profiles in the driver. This information allows you to create an SLI profile for games that don’t have a built in profile yet, or if you want to force a mode in a certain game.

This isn’t without faults though; the system is still not exactly 100% user friendly. First, you must edit the Coolbits registry file and then apply this registry setting. Next, you have to use the advanced menu systems and go in and manually create a profile, select the .exe for the game, and then select what mode to use. Note that you might, however, select a mode that doesn’t work 100% correctly in the game. You may choose SFR and find that it doesn’t work well, or you might choose AFR and find it doesn’t work well. If this is the case, you’ll have to go back and edit the profile.

Unfortunately, there is no way to know which mode will work best in each game without testing the game yourself. NVIDIA does this testing for you for games they support, and those profiles you see programmed in the driver are using the best setting. For those games that don’t have a mode set, you have to play the game using trial and error in both modes to find the best mode. Still, we are glad NVIDIA is giving us the ability to create our own profiles for games that do not yet have an SLI profile set. This feature gives us much more control, which we like.

Some Bugs To Be Aware Of:

Make sure to check out the release notes PDF for this driver. There are some open issues that will be fixed in the next driver release that are worth noting.

“GeForce 6 Series, SLI: Overclocking using Coolbits does not work when SLI mode is enabled.”

and

“GeForce 6800: The Temperature Settings in the Display Properties reports an approximately 20% higher temperature than with the previous driver version.”

and

“GeForce 6 Series, SLI: After exiting a 3D game, the NVIDIA clock frequency remains at the higher 3D-performance frequency instead of reducing to the standard clock frequency.”

There are also some game specific problems which we did encountered in our testing such as

“GeForce 6800 GT/Ultra SLI, Windows XP: Running the game Chronicles of Riddick with SLI enabled results in corruption or application crash.”

and

“GeForce 6 Series: Stuttering appears in different portions of the game EverQuest2.”

We will explain more on the following pages in this article.