Wow -you have a lot of hard drives in your downloads rig! I don't notice slowdown much here in Japan, unless I'm trying to get onto bandwidth heavy American sites during the morning (14 hour time difference so it's night there). I guess it's time to go shopping for a new router.
Yeah I archive file as a hobby kinda (32 terabytes!) anime ect. yeah there's more but not going to say what) , also, I have the means, and I have a lot of friends that don't (those that do um . ., "grease the wheels" shall we say) and I host files/ allow them access to my FTP server, I also use it for my consulting business, allowing me to right off all the hardware, and my internet bill (and phone and HDTV gotta love bundles! as a business expense during tax season.
A 10/100/1000 router from brands like Linksys/Cisco (I use them exclusively! you can't get any better) for about $60-$80 USD / 5,300 - 7,200 JPY.
P.S. I adore Osaka, my favorite town in Japan! I eat my guts out every time I go there A( I drink far too much as well, as every time I go, I end up being taken out by reps from the companies I work for)! I've gotten my picture taken with the kui-daore clown 2 times (soo sad he's gone!)! Only been to 1 tigers game, people are so strict about cheering and talking during play. !_!'
It's weird...
From my LAN rig down stairs (also my HTPC (in a HAF932 (in my rig stats) I use it for SSH tunneling so it's on 24/7 and other stuffs)
The upload is almost dead on for whats the max (2.7mbps) for my connection, but the download is still less than half of what I have been known to pull ( about 15mbps).
EDIT: slightly "better"