Did some research on what the reason is why you get better performance when you change settings: In the NVIDIA control panel it will say " NVIDIA recomended(sli)" That is because they gave it that code in the driver settings. When they set the "predefined number of gpu to use on sli rendering" to max 2 GPU's count it will show "alternate frame rendering 2" in the CP , when the set it to max 4 GPU's it will show "NVIDIA recomended" in the CP. This should have no effect on performance , I always use max 4 GPU count , even if I have got to make my own sli profile. And that works the best for me. You can check the driver settings and rendering modes with "nvidiaInspector" http://forums.guru3d.com/showthread.php?t=333518 You never know that with this driver (quadro) that has only got optimized support for 2-way sli and not 3-way or 4-way , this profile with max 4 GPU count gives rendering problems in some cases. A quote from the release info of this driver : Existing Support: * Support for the Open Computing Language (OpenCL) 1.0 in Quadro FX Series x700 and newer as well as the FX4600 and FX5600. * Supports NVIDIA SLI technology (two-way SLI) for DirectX 9, DirectX 10, and OpenGL on SLI-certified Intel X58-based motherboard based system from select OEMs. * Support for DDC-Ci/MCCS over the DisplayPort AUX channel. * 10-bits per color (10bpc) DisplayPort support for full-screen applications on supported products. * Users without US English operating systems can select their language and download the International driver here. So you see that when the default game profile (like Call of duty BO) has got a predefined max GPU count of 4 to use in sli , that with this Quadro driver it can give problems. So changing sli rendering mode in the CP to "Alternate rendering 2" can solve the problem in the quadro driver. I'm not saying that this is a fact ! Don't shoot the messenger.