Using Multiple GPUs does not improve simulation time

[cmcc]

Hello!

I'm using a setup with two GPUs (RTX 2080 Super) and attempting to analyze if it's worth it to purchase another with two GPUs, or just go for a single. Currently what I'm seeing in the two log files is this:

Single GPU
The following hardware configuration has been chosen for the simulation:
Device (0): GeForce RTX 2080 SUPER using 824.146 MB
Elapsed time for 'Preparing for time update' was 00:00:17 wall clock time.
Starting solver CUDA (hardware accelerated).
Time Update
Simulation performed 66994 iterations.

Dual GPU
Device (0): GeForce RTX 2080 SUPER using 414.731 MB
Device (1): GeForce RTX 2080 SUPER using 414.731 MB
Elapsed time for 'Preparing for time update' was 00:00:17 wall clock time.
Starting solver CUDA (hardware accelerated).
Time Update
Simulation performed 66994 iterations.

The resulting completion times have minimal differences (27 m 14 s vs. 22 m 23 s) and is likely due to the reduction in memory usage on each GPU. Am I missing something or is there negligible difference between 1 and 2 GPUs?

Thanks

cmcc