The main differences are:

• The CPU side threading has been removed. The sample now leverages async compute as follows:
  • Once the n-body simulation finishes, the results are copied and the next simulation step is immediately kicked off. This allows the simulation to overlap with the rendering. The original sample would synchronize such that either the graphics or the compute queue was in use. Now, the compute queue is kept busy 100% with the n-body simulation, and the rendering is running concurrently.
• The sample has slightly higher graphics load by using larger particles (increasing the load on the blend units) and using a noise function to modify the color of each particle (increasing the compute load)
• The sample is now queuing up to 4 frames, instead of 2, making sure that the GPU is always filled with work.
• The sample has been instrumented to measure the frame timing.
• The number of particles and the block size has been slightly increased to increase the amount of computation. It uses now 16384 particles and work groups of 256 threads each, resulting in 64 fully filled invocations. The original sample uses 10000 particles and work groups of 128 each.