External eSATA hard drive - slow transfers on fat32, fast on ext3

[anthropodeus]

I have a ~500GB external HDD connected to my laptop via eSATA. There are two partitions on it: a small one that is fat32 and a large one that is ext3.

files transfer to the ext3 partition at normal eSATA speeds - about 33MB/s. but the transfer speed to the fat32 partition is only around 10MB/s max, and usually slows to around 6MB/s as the transfer proceeds.

if i change the options from the ext3 partition from "relatime" (the default) to "rw,auto,user,sync" so that i can unmount it without going through root, the transfer speeds to the ext3 partition ALSO slow down to ~10MB/s.

so what is it in the "relatime" default that makes mount recognize the connection as full eSATA? and how can i make the fat32 partition transfer at full eSATA speed?

here's the relevant stuff from /etc/fstab:

#	<file system>					<mount point>   	<type>			<options>					<dump>	<pass>
#
#External Hard Drive:
#
# /media/Archive was on /dev/sdb3 during installation.
	UUID=2d840736-429e-4984-9f75-7ad1c532c9b0	/media/Archive		ext3			relatime					0	2
# /media/ExternalAudio was on /dev/sdb2 during installation
	UUID=49E2-61B0					/media/ExternalAudio	vfat			rw,noauto,user,sync,shortname=mixed,utf8	0	1

[logos34]

I wonder if it's the way Hal is mounting the vfat partition (vs. an interface issue). Related discussion here (but concerned with USB). Maybe add the fstab mount options async and flush

atime vs. noatime and relatime is explained here. (speed diff in ext3 is due to atime/sync excessive disk writes)

There was another article explaining noatime and relatime that I read some time back (when I was trying to eliminate constant disk activity), but I can't seem to find it now. hmm