What version of Particular are you using? Older versions were susceptible to two issues that are both resolved (I think) in more recent builds.
1) It’s possible that Particular is not properly invalidating the cache, so you end up recycling old frames instead of rendering new ones. Clear your cache.
Ae CC/CC2014/CC2015:
Edit > Purge > All Memory & Disk Cache
Ae CS6:
Preferences > Media & Disk Cache > Empty Disk Cache
2) If your particles are popping on and off near the edges of your frame, this may be due to a problem with how Particular culled the frustum [link].
Basically, I think Particular did not take the true size of a particle into account when figuring out if it should be rendered on-screen or not. Large particles that are near the edge may be erroneously removed from the scene because their center points have gone outside the boundaries of the solid — even though a significant amount of the particle is still on-screen. A workaround is to increase the size of the solid to which Particular is applied, so that the popping happens out of view of the comp.
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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