I just opened up a blank cap and put 18 particle emitters there each at a rate of 2400
and it was still running at 90 fps, and my system isn't nearly as fast as the one you're claiming
I've made a demo that used particle emitters with huge textures (1024x1024) and tons of sprites with textures at that size or larger, with 50 or 60 instances of ik animated characters using those textures to make up their bodies without experiencing the kindof slowdown you're talking about
i don't think it was your intention to spread disinformation, but a question like "why is this slowing down" in help/tech support might have been a good idea, since newbs to construct might see this topic and assume it's really true. know what I mean?