After effects cc render time issues I recently made a video 3 minutes long with trapcode particular, 2 light layers and some simple expressions for particular (wiggle and time).
Rendering in quicktime h264, 1080p 30fps.

I started to render the video and on first it showed 28 minutes remaining. I was extremely happy with that. Came back 30 minutes later and now it was estimating 1h 20 minutes. Came back hour later and now it was at 1h 54min.
Although the rendering was now going for more than hour. The time kept increasing. 

I decided to stop and use adobe encoder, with h264 and matching video settings high bitrate. Encoder at the start gave me 1hour and later increased that again. 

So few hours later I am using after effects built in rendering and time remaining is 1hour 30 min and elapsed is at 3hr 44min and more than half way through rendering.

How could it be increasing all the time? I am using after effects for about a month now so I don't know all the hacks. I am using intel i5-6400 2.7ghz with 8gb of ram and 4gb of ddr5 gpu geforce gtx 750 ti.

Would it help if I would render particles separate with alpha channel and then add it to full composition? Would that reduce time?

Sorry for such bad explanation. English is not native for me.
I usually export as a ProRes Quicktime movie from After Effects directly, then convert my ProRes file to h264.  I keep the ProRes as a master file, and compress the h264 as needed.  Also sometimes restarting AE before rendering fixes any slowdowns.  If the particles are using large (greater than 200x200 pixel) layers for their textures, this will make things render very slowly.