2x Geforce GTX 1080


The configuration of my setup is:
Intel i7 6700K
nVidia GeForce GTX 1080

I would like to improve the performance of my system.
I wonder if I add a second GeForce GTX 1080 video card how much will it boost the processing time ?
Anyone has 2x GTX 1080 video cards ?

I also saw that mostly the CPU is under high load (up to 100%) whereas the GTX 1080 GPU is at most at ~30% load (at least from what I noticed).

Would it have more impact a better CPU than a second GTX 1080 video card ?

Thank you !

Intel i7 6700K is a pretty great photogrammetry CPU already from what I understand. I don’t think upping to a (much more expensive) better CPU will create such a massive boost in performance, but I can be wrong. Also, check your GPU load while running the “reconstruction” phase, this is generally where a GPU is most heavily used, whereas in alignment phase it’s mostly the CPU. I think I remember reading somewhere that a second GPU should improve reconstruction performance like 50-70%, so not double it, but still significant improvement.

Thanks for the great news.
Actually I can borrow a second GTX 1080 from a friend and have a performance test.
However my video card is from MSI and his is from Asus.
I wonder if there is a problem if the video cards are not identical.

I found in another thread Multi GPU that we can use different GPUs.

Hi Florin Barbuceanu

Its not a problem to mix diff cards :smiley:

get the MSI afterburner and make some screenshot when reconstructing model as we have observed quite interesting stuff regarding speed of the 1080s…

I’m running 2 x 1080 with a 6900k.

1080’s only help while creating depth maps.

so if thats taking a while it will speed that up.

it depends your scenes on how much it will help vs a faster cpu.

but if you have lots of photos/high res. gpu’s will help.

if you have large area’s and want high detailed meshes, they get more cpu intensive.

for the project i have been doing, I find the cpu the bottle neck. normally around 20% gpu time 80% cpu with this setup.

in and old setup with 1 x 770 with 3930k. I found it around 50% gpu 50% cpu.

I haven’t tested rc on my 6700k (if it was floating license i could test it). but i suspect it would be pretty good. I do find parts of the processing can drop down to single core in parts. and 6700k would do quite well there to make up for less cores.

I do also notice 1080’s, running at around 30% a lot of the time. (they normally start out at 90%-100%)

Hi Chris

Thank you very much for the valuable info.

I also noticed that the GPU Load starts at 99%-100% but soon after it comes down to ~30%.
In the mean time, the CPU stays at 100% most of the time.
So my impression is also that the CPU is the bottleneck.

My feeling is that a dual CPU motherboard and two CPUs with significant more cores might boost the performance better than a second GPU. Would you agree with this ?