Aaaww cripes !!! - Here we go again !! ...
Ok, all the wrong answers can stop now !!.
90k / sec is perfectly respectable, and yes it *does* depend on not just Your internet connection or the PC, it *IS* a combination of both factors.
The primary hardware in Your system makes a difference in Your connection spedd due to "bus speeds". If You have a land-based internet connection with a modem, You probably hooked it up to your USB connector just out of habit. If Your system has a network connector instead (RJ45, accepts a Cat5e cable) then You should be using THAT port instead, any systemn newer than say 2001 will have a 10/100 port back there that handles 10Mbps to 100Mbopps efficiently. USB support varies with the USB versions and internal hardware revisions, as well as possibly being limited by motherboard driver software.
I use a PCMCIA card modem on a laptop, which I switch between a PCMCIA internal adapter for my desktop, I regularly average 90Kbps on most Internet dloads while running P2P software minimized and at 70% maximum connection usage. My provider supports up 2Mbps max but I've easily passed that occasionally thanks to EDO rev A.
I use a Samba PC 2.2Ghz with 256 megs of RAM (at 100Mhz even), and my laptop has a 2.2 Intel mobile P4 with 512 Megs of DDR RAM. They both get about the same connection speeds, because I have a PCMCIA card, and cannot use a network port for either system although they both have themn built-in.
You're doing fine, and the true test is how fast a largely graphic and scripted website comes up for You. if you've tweaked all the possible settings for Internet Explorer, all it's add-ins, Your system's virtual memory, and any network hardware ports in Your system for max performance, then You may want to try the network connector if possible with Your modem.
Otherwise, if it ain't broke, don't fix it. Some people in some areas actually still have to use dial-up, and that runs at 15kbps on average due to most hardware limits with modems.
Good luck!.