tftp transfer painfully slow

I am using HPA's tftp server for PXE boot. When I try downloading an image from my tftp server using curl, the transfer rate is less than 3 MB/s, even on my 1Gb network. curl -o initrd.gz tftp://192.168.0.4:69/boot/debian/initrd.gz Is this an inherent limitation of the tftp protocol, or can this be configured?