Max # of h.264 decoding video streams

I work for a security firm and we are building a workstation that has dual P4000s. This workstation needs dual monitor output and be able to decode multiple h.264 streams. At most, Monitor 1 needs (5) concurrent videos streaming and monitor 2 needs at most (3) concurrent videos streaming. The video is coming from IP video cameras. We are getting poor performance where the frame rates are ‘rubber banding’ and vehicle traffic appears to speed up and slow down. It does not do this on any other workstations. Does anyone in this form have any insight as to what might be happening or have some advice on how to improve video performance?