NVIDIA’s GeForce GF100 Under the Microscope

Geometric Realism & Tessellation to the Next Level

In past pages we talked about the architectural advances that have been made in order to facilitate high-end, efficient performance. Now we get to see how all of these new features on the GPU work in concert to increase the overall performance of the GF100 in next generation games that will use tessellation and other DX11 features to attain geometric realism. NVIDIA claims up to an 8x increase in geometry processing horsepower versus their previous hardware generation.


Tessellation Performance


For those of you wondering what the tests above represent, the first three on the left show tessellation performance with an increasingly higher level of geometric complexity. The next two focus on situations that use a combination of geometry processing and DirectCompute operations to render a high-resolution scene and finally the last test is run on a direct draw call from Unigine’s tessellation engine.

We know from experience that while ATI’s 5000 series was the first on the market with DX11 compliance, it has some serious issues rendering scenes with more advanced DX11 features. NVIDIA meanwhile made an investment towards geometry performance which should vastly improve DX11 performance.


Unigine: Heaven Performance

The chart you see below is from the Unigine engine benchmark, 60 seconds is taken from the walkway section of Heaven benchmark that has the most tessellation.


NVIDIA states quite emphatically that with their GF100 series of cards, the developer can deploy a lot of geometry (tessellation) into a scene without a huge drop in performance. With the parallel workloads being performed, this new architecture works toward uniform performance instead of having sudden drops as seen with competing solutions. As we already mentioned, the HD 5000 series isn’t tailor-made for a DX11 environment while NVIDIA’s architecture was designed from the ground up to do just that.


Geometry Shader performance

NVIDIA showed off one more bit of information about DX11 performance which was from a Microsoft DX11 geometry shader toolkit. The results you see below were taken during the rendering of two separate passes which ask the GPU to process up to six cubemap faces in one pass.


Past APIs needed to have polygons processed on the CPU and then shipped over the PCI-E to the GPU which requires a huge amount of computing horsepower and is inefficient. DX11 allows all of the operations for higher-end functions like tessellation and geometry to stay on-chip, but NVIDIA takes things even further by ensuring the GPU core processes everything without even sending it to the GPU’s local memory.

Meanwhile, DX9 didn’t allow a developer to create geometry on the GPU which DX10 allowed for limited geometry to be created. However, now with DX11, developers can do so even though it takes massive horsepower to process it and compute the instructions. This is where the GF100’s parallel geometry processing architecture comes into play since it allows for efficient caching of data without having it run into a memory bottleneck.