Altera Avalon Uart performance problem

The JTAG uart works ok for the console port, but I stopped using it because of the annoying CTRL-C issue with nios2-terminal.

Our end application is going to be using multiple RS232 UARTs for communication with multiple external devices. All of these will be running at 115200 baud.

I was trying to test a single port to validate the design. The Nios uart and even the FIFO-enabled Cal_Avalon_Uart that I've been working with are preferable to the Open Cores uart because of their small footprint. I just don't understand why I would be dropping characters, even with a FIFO'd uart.