DirectX 12 Explicit Multi-GPU Performance Review with Ashes of the Singularity
Published: 24th February 2016 | Source: Oxide Games | Price: |
R9 Fury X + GTX 960 or R9 380 - Can I add a low end GPU to a high end one?
In Ashes of the Singularity the game uses a Multi GPU rendering mode called AFR, which allows each GPU to work on every other frame in turn. This means that for both GPUs to work together the fastest GPU will have to work at the same speed as the slowest GPU, which in turn means that an Explicit Multi-GPU setup will work best if both GPUs are evenly matched.
Given that Explicit Multi-GPU allows any GPUs to work together, it is not recommended that you pair together GPUs with a vastly different amounts of computational power as the fastest GPU will be limited to the speed of the slowest GPU.
In the examples below I have paired together a GTX 960 or a R9 380 with a R9 Fury X, a GPU that is more expensive than both of these lower end GPUs combined. One thing to note here is that the R9 Fury X is CPU limited in this graph and is not operating as fast as it should, but these were the highest settings that I could get the GTX 960 and the R9 380 to run without hitting VRAM limitations.
We can see here that by adding an unsuitable GPU (one that has less than half of the computational power of the higher end GPU) will result in a performance decrease, as simply put the higher end GPU, in this case the R9 Fury X, will need to hold itself back to much for any performance gains to be possible as both GPUs need to run in sync.