NVIDIA's SLI: Part 2 - 6800U & 6800GT

Far Cry

Publisher: Ubisoft

Here, we are using the full retail version of Far Cry patched to version 1.31. We did a manual run through of a section of the Factory level, which is both indoors and outdoors - the majority of our manual run through is taken from the start of the level, which is all outdoors. We also played through a section of the Fort level to ensure that our settings were playable in other graphic-intensive environments.

Anti-Aliasing and Anisotropic Filtering were controlled from inside the game, and thus we left the drivers set to "Application Controlled".

Far Cry is a different title to both Half-Life 2 and Doom 3 in many respects. Firstly, Far Cry makes use of a Split Frame Rendering method, which means that the load-balancing bar moves up and down the screen. We've got no doubts that the geeks amongst you will find it fascinating how the two video cards load balance the scene - worth checking out for curiosity’s sake.

The game uses a custom load balance algorithm to allocate equal load to the two video cards, in order to gain the best-possible performance increase in the title. For the sake of being complete, nvapps.xml contains the following code for Far Cry:

   < PROFILE Label="Far Cry">

      < APPLICATION Label="FarCry.exe"/>

         < PROPERTY Label="multichip_rendering_mode" Value="4C00002" Itemtype="predefined"/>

   < /PROFILE>

Secondly, Far Cry was the first title to implement High Dynamic Range Rendering in to its graphics engine. For those of you who want to read about how this affects the image quality in the title, it would be well worth giving our Far Cry patch 1.3 evaluation a good read through. Back then, we mentioned how resource hungry HDR was - even a GeForce 6800 Ultra struggled to deliver a smooth gaming experience at anything above 1024x768.

We found that the two Point of View GeForce 6800 Ultra's, running in SLI mode, were capable of using HDR at a reasonable resolution, with a good frame rate. We were able to play through Far Cry at 1280x1024 0xAA 4xAF with Maximum Quality details, and r_HDRRendering set to '2' on two GeForce 6800 Ultra's. As we mentioned in our Far Cry patch 1.3 evaluation, you cannot use HDR and Anti-Aliasing at the same time with NVIDIA's current GPU's. It remains to be seen as to whether we could possibly use Anti-Aliasing and HDR with a next-generation GPU from either ATI or NVIDIA - we'll inform you as soon as we know ourselves.

Using two XFX GeForce 6800 GT's in SLI mode, we found that we could enjoy smooth game play throughout the title at 1600x1200 2xAA 8xAF with Maximum Quality details. The GeForce 6800 GT SLI lacked the speed to make use of High Dynamic Range Rendering at 1280x1024, so we opted for the higher resolution without the additional lighting effects.

The single Point of View GeForce 6800 Ultra was capable of a smooth frame rate at 1600x1200 with 0xAA 8xAF and Maximum Quality settings, while a single XFX GeForce 6800 GT managed a solid frame rate at 1280x1024 0xAA 8xAF and Maximum Quality settings.

You will notice that the average frame rates are considerably lower on both the GeForce 6800 Ultra SLI and the single GeForce 6800 Ultra configuration. This did not affect the game play, and in the case of the GeForce 6800 Ultra SLI, we found that the frame rate remained very constant throughout our manual run through - this gave us a hint of a smoother gaming experience, as there was less variance in the frame rate in general.

When we tried to increase the details on the XFX GeForce 6800 GT SLI, we experienced a harsh drop in the minimum frame rate, which resulted in a large amount of choppiness. The same happened on the single GeForce 6800 GT too when we applied 2xAA at 1280x1024.