The recommended replacement product for the PIX 515 is the PIX 515E. This platform offers enhanced performance and integrated hardware-based IPSec acceleration (certain models) at a comparable price point. The PIX 515E uses a high-performance 433-MHz Intel Pentium Celeron processor, compared with the 200-MHz Intel Pentium MMX processor of the PIX 515-providing up to 36 percent improvement in firewall throughput. In addition, the PIX 515E sports the same low-profile 1-rack unit (RU) chassis. PIX 515E systems support the same type and quantity of interfaces that are supported on the Cisco PIX 515 Firewall.