Going from 32 GB to 64 GB

[madman7]

I took out 2 16 gig memory modules and put in 2 32 gig modules. I found out that I can't run the 64 gig as aggressive as the 32 gig. I did get the 64 to run at DDR5-6000 but I couldn't use aggressive settings in the BIOS memory settings like the 32 gig. I would get random black screens and had to power down and restart. I haven't tried competitive setting yet to see if that might work.
The 32 and 64 were both G. Skill Flare X5 memory.
Is higher memory count harder to get running at more aggressive timing?
Specs in signature.

 

[JLK03F150]

Is higher memory count harder to get running at more aggressive timing?

From what I have read here & on other forums, yes.
If memory serves me, being able to only reach DDR4-4800 to 5600 is common (or am I confusing that with 96-128GB?).