Fedora 11 did significantly better than Ubuntu 9.04 when it came to 64MB writes with 32 threads using the Threaded I/O Tester to benchmark the Serial ATA disk under Ubuntu and Fedora. Ubuntu 9.04 had a significantly higher latency. This large difference is likely due to performance improvements found in the Linux 2.6.29 kernel, which Fedora uses, as well as the EXT4 file-system.
While the 64MB writes were faster under Fedora, the 64MB reads were better with Ubuntu.
NetApp's PostMark had more transactions per second under Fedora 11 compared to Ubuntu 9.04 -- a 38% difference.