[FWTools] Trying to translate gtif ASTER image to jpg but v. slow

[Simon Hook]

Hi,

I have a 3 band, byte ASTER satellite image that is stored as a geotif 
that I want to convert to a jpg with a world file. I run the command:

F:\Windows\geotif2jpg>gdal_translate -of JPEG -co WORLDFILE=ON 
aster_vnir.gtif aster.jpg
Input file size is 5796, 4888
0...10...20...30...40...50..

However, thats the output after about 10 mins, FWTools takes about 20 
mins per scene and I want to convert hundreds of scenes. Is there any 
way to speed up gdal_translate. I tried the:

gdal_translate --config GDAL_CACHEMAX 512

and then ran the gdal_translate but it is still v. sloow.

Many thanks,

Simon