RealFlow’s Dyverso solver is highly optimized for CPU multi-core and many-core processors. Some GPUs, on the other hand, do not have enough computational power to outperform a 8 or 12 core processor - which is common hardware today. For this reason a GPU-based simulation can be slower than a pure CPU-based simulation.
We have observed that the number of GPU cores makes the difference. As a simple rule we can say: the more GPU cores, the better. A simulation with a Nvidia Quadro K6000 (2880 cores) is about 3x faster than an Intel Core i7-3930K, for example.
Nvidia's GTX 9 and 10 series, or comparable AMD cards, offer a very good price-value ratio and these boards are perfectly suited for Dyverso simulations. The actual speed boost depends on your hardware.
Only the fluid solver is GPU-accelerated, but some processes, e.g. fluid-object collision, are entirely calculated by the CPU. In scenes with many collision objects and other, computationally expensive elements, you might not see a boost in performance by enabling the GPU. These limitations will be removed in future versions of RealFlow where the simulation pipeline will be executed entirely on the GPU.
Typcial cases with limited GPU-capabilities are simulations with the → "Ocean Force", → "Sheeter", and → "Crown" daemons.
This is a typical effect when GPUs are not supported or when the GPU is slower than the CPU.
The real influence of the GPU can be seen where Hybrido particles are involved: simulations with a high number of particles (compared to the number of cells) will normally perform better. The creation of the fluid’s distance field or displacement is entirely simulated by the CPU. This also applies for the generation of Hybrido secondary fluids (splash, foam, bubbles).
The influence of the GPU on Hybrido is comparable to an additional (single-core) CPU. Therefore it hardly makes any difference whether you are using a high-end board or a mid-range graphic card. Hybrido on the GPU can be considered an experimental technique.
Only the fluid solver is GPU-accelerated, but some processes, e.g. fluid-object collision, or Hybrido secondary fluids (splashes, foam, etc.) are entirely calculated by the CPU. In scenes with many collision objects and other, computationally expensive elements, you probably won't see any effect with the GPU enabled.
This is a typical effect when GPUs are not supported or when the GPU is slower than the CPU.
These simulation engines are not GPU-accelerated.