Sure. Out of curiosity, what does your hardware look like? (GPU, mainly) And at what resolution are you rendering?
There are also a few things you can possibly tweak that may make individual frames render more quickly. Things that are transparent and things that are reflective slow things down, for example, because it adds extra calculations for iRay. So, if you can avoid shiny surfaces, mirrors and windows, that helps.
Obviously, having a scene be well lit helps iRay converge more quickly. If you're using 4.11 or 4.12, you can (as was suggested earlier) limit the number of iterations and then use the denoiser to help.
There's also a setting called "Max Path Length" in "Render Settings > Optimization". (It's not really path length, but really the number of bounces.) By default, it's set to -1, which means "as many as iRay thinks it needs," but you can set it to something like 5-6, and that sometimes helps. Doing that can sometimes cause problems with how eyes come out, however, because of the way that they're constructed.
Essentially, anything you can do to speed up the rendering of one frame of your animation gets multiplied by the total number of frames.