fc6 dvd read performance degrades with mkisofs joliet option

[Skunk Worx]

Hi,

I use FC6 to master DVDs and have noticed if I add the -J option to the 
mkisofs command the read performance on the final dvd is severely degraded.

For example mastering a DVD image with RockRidge and ISO9660 alone 
yields about 200 mb./minute read performance on my media.

Adding the Joliet option to mkisofs command line degrades the read 
performance on the final dvd to about 75 mb. per minute.

Is this expected behavior? I used the same media and drive (dvd-rw) and 
blanked with /dev/zero between cycles then duplicated the test twice to 
be sure.

Thanks,
John