Don Bowman (pictured), Sandvine's CTO, sent me a comment on my coverage of Sandvine's recent product announcement ("Sandvine - New High-End DPI"- here), referring to the way performance numbers should be considered:
"With communications service providers worldwide under pressure to rein in operations costs, performance density is as important a consideration as top-line performance. Fortunately for operators, Sandvine’s PTS offers the best of both worlds without sacrificing either: industry-leading port and performance density combined with clustering technology that efficiently delivers massive scale. For instance, the PTS 24700 delivers 30 Gbps of inspection throughput per RU under real-world business intelligence, real-time charging and management policy load. As a direct consequence, Sandvine achieves the required top-line performance in fewer rack units than our competitors, providing considerable operational savings versus alternatives".
See the DPI Product comparison (here) for rack units, port density and vendor's throughput numbers.