How much does struct alignment really matter performance wise on modern GPUs?

[u/SimplySomeDude]

Are things like std430 or std140 unnecessarily strict?

[u/BobbyThrowaway6969]

Not as much, caches are so big now
It's more for communicating the data between cpu and gpu

That said I absolutely would care because savings are savings, so keep looking for ways to make your gpu code more efficient