Working with IES lights

[RobSteady]

I've got a scene with two different instances of IES lights (5 and 5).
When both are switched on, one renders fine but the other instances seem very dark and rendering very slow.
When I switch the other one off they render ok.
Both lights have max samples.

Do I make something wrong?

[rfox]

check the visible button and see how it goes, apparently i experienced the same way like you had, i instanced 120 lights with visible unchecked and it won't lit at all.

[gabrielefx]

turn on Octane proxy and check the rotation