You "NEED" a router only if you are using wireless. Also, a router is better and easier if you want to have 2 or more PCs using your modem. Most routers have a firewall feature for added security.
http://www.broadbandinfo.com/internet-access/hardware-and-wireless/cable-modem/splitter.html can cause packet loss or disconnections, but since you have no choice just get good quality splitter(as been recommended) i personally give up on cable long time ago for this exact reason-signal strength was very weak,causing all kind of problems.. i was first in line for fios in my neighborhood.
bs or not, but i'm not alone on this one- http://forums.speedguide.net/showthread.php?t=166388 http://www.wirelessforums.org/members-lounge/router-firewall-vs-software-firewall-503.html http://www.computing.net/security/wwwboard/forum/8806.html i would use software firewall from time to time on computer,which i'm using for browsing, etc for only one reason-to see, which applications want to go out from computer, when I connected to internet.
Be aware that if you install SSD, it will install a hosts file that will redirect some website to an unresolvable address. This is for your 'protection.' Where it gets VERY frustrating is not knowing it does this when you're visiting a site that gets paid by the click throughs. An example is www.hot-deals.org. With SSD, when you click some (but not all) of the links, the redirect site is part of the hosts file that SSD installs, and the page you want to come up won't. So, if you have SSD and you can't get to a site you think you should, check the hosts file and see if your destination site is being blocked. Frustrated the hell out of me until I figured it out. Other than that, it's a great program, albeit slow as hell on an older machine.
i ran the speed tests. what number am i looking for? which one is important for trading? download speed upload speed ?