The NXP LPC2387FBD100K is a 16/32-bit ARM7 microcontroller in the LPC2300 series, clocked at 72 MHz with 512 KB of on-chip Flash and 98K x 8 SRAM. It includes Ethernet MAC, USB OTG, two CAN channels, SPI, I²C, and UART interfaces.
72 MHz ARM7 core — bus timing and throughput
The 72 MHz clock on the ARM7 core is the practical ceiling for this core without a cache. For a TCP/IP stack handling Ethernet frames, or a CAN gateway forwarding messages, that clock gives enough headroom to run the stack and application code without external RAM for moderate traffic loads.