My younger sister & I are connected to the internet via Linksys WAG200G (cabled) with a package speed of 512kbps. Whenever I’m downloading, my problem starts whenever she starts downloading files (especially from Rapidshare). My download bandwidth dramatically drops from 57Kbps to only a maximum of 15-18 Kbps, while I suppose, she’s getting about 40+Kbps (for a total of approx. 57Kbps for a 512kbps connection).

My PC’s specs:
Intel Core2CPU 6420@ 2.13Ghz, 2GB RAM, NVidia GeForce 7100S, Win XP Pro

Her PC’s specs:
Intel Pentium 4 CPU@ 2.44Ghz, 2GB RAM, NVidia GeForce 5500, Win XP Pro

How come that she’s getting 2/3 of the bandwidth whenever we download at the same time from Rapidshare while she don’t owns a premium account with Rapidshare & I’ve got one. Also, we’re using the same IDM 5.12 Build 11 with the same settings?

Moreover, I’ve used every tweaking softwares I know such as TCP Optimizer, FullspeedConnect but to no avail. Can anyone help???

BTW, I've already upgraded the router's firmware with the latest from linksys & I'm using KIS 7.0.0.125.

Is there a software or program that I can use to limit her bandwidth consumption? Though were not in a LAN? Can I tweak my LAN settings so that I can always have priority during downloading?