Isn't RT performance increase supposed to be linear ? Benchmark suggests otherwise

[JezUK]

My 4 x 1080ti GPU are coming in at 19 seconds, whilst 7 x 1080ti's are coming in at between 15-16 seconds ??

(before, when I had just 2 x 1080ti's it was something like 28 sec, from memory).

[savage309]

V-Ray Bench scene is not set up very well for multi GPUs. It needs to have more rays per pixel by default.
We will change that in some of the next major releases of V-Ray Bench.

Best,
Blago.

[JezUK]

Thanks Blago - this is important for me as I plan this year's upgrade (i.e. whether to go ahead with my 7 x GPU open rig) or not