slow USB HD with linux (busybox)

Hi there,

I'm rather a busybox noob, so I hope to find some help here:

I use busybox on my Siemens Gigaset settopbox together with VDR. This
works very fine, but unfortunately I seem to be the only user with this
combination that experiences a very slow USB HD performance.

Strange thing is, that the HD is running at a Windows PC perfectly with
~25MB/s.

benchmarks with dd result in the following:

# time dd if=/dev/zero of=/media/LAUFWERK_G/out.test bs10%24 count10%0000
100000+0 records in
100000+0 records out
real    1m 49.80s
user    0m 2.30s
sys     0m 34.70s
# time dd if=/media/LAUFWERK_G/out.test of=/dev/null
200000+0 records in
200000+0 records out
real    0m 46.59s
user    0m 4.08s
sys     0m 23.64s

which is about 4MB/s and worse.

mount results these mount options:
/dev/sda1 on /var/media/LAUFWERK_G type vfat
(rw,noatime,nodiratime,nosuid,nodev)
Hence it's not synchronized.

Any Idea how I could debug this further? ~4MB/s is bigger than low-speed
USB, so it does not seem to be a problem of the wrong USB driver...

I would also say that it's no problem of CPU performance, because there is
some community of users with the same HW and don't experiencing this
problem (but they don't have an idea what's wrong here, either).

So this mailing list is my last hope to get things going...

Cheers,
Hauke