Suggestion from John and my reply.

> We have achieved very high rates, but only with some care.

> The biggest issue was to make sure when you compile the CAEN driver for the A3818 board that you turn on the MIDAS switch.  Without that problems occur with some 
> probability given by the number of bytes processed - which translates into very soon if you have a high rate.  (The underlying cause is that both MIDAS and the A3818
> use unix Alarm signals, but the CAEN folks have a compile option to turn this off.)

> We use as little as possible of the CAENDigitizerLibrary - instead we program the registers directly on the board.

> There is still some kind of memory leak which we have not yet tracked down, so every few hours we shut down the frontend then restart it. 

We use A2818 (PCI) - fiber - V2718 (Bridge) - VME - V1751.
I actually didn't find a MIDAS switch in the Makefile.