The biggest benefit of the Reality engine is that it works with or without the GPUDirect feature. Reality engine has an additional option to use GPUDirect for accelerating communication with video I/O devices. And also have the liberty to use it without the GPUDirect feature. This flexibility offers the choice to our users. GPUDirect is an optimized pipeline for frame-based video I/O devices. The combined solution delivers the capability to maximize the performance capability of the GPUs.
GPUDirect for Video is a technology that enables to take faster advantage of the parallel processing power of the GPU for image processing by permitting industry-standard video I/O devices to communicate directly with NVIDIA professional Quadro GPUs at ultra-low latency.
You can also find more information on this link: http://developer.download.nvidia.com/devzone/devcenter/cuda/docs/GPUDirect_Technology_Overview.pdf
You can enable GPUDirect to eliminate CPU Overhead. USEGPUDIRECT property can be found in ENGINE CONTROL node under VIDEO I/O category. The below image shows GPUDirect is disabled, which is by default in the Reality engine.
To enable GPUDirect, click on USEGPUDIRECT option and turn it to TRUE. Below image shows GPUDirect is enabled.
To disable again, simply click on the cross mark.