RenderTexture stall

I am running some GPGPU stuff in a very basic shader (it even runs on iOS). The data I get back from the stream I'm writing to is correct and everything is working, however the frame rate is really low. I believe this is because retrieving my data off the GPU requires a CPU stall until all rendering is complete. However, my data isn't time sensitive.

If I were writing this in OpenGL, I would double buffer my output texture, forget about synchronization, and get my data back the next frame without the CPU stall.

Is there a way to do this in Unity, or do all RenderTexture operations require immediate sync? Can render textures be double buffered in this way to avoid the stall?

Cheers

Jesse