Macbook browsing woes

Don't know if anyone else is experiencing this,and I know this is for hardware issues only(don't know if it's hardware or software), but in Firefox or Safari, when I open a page my black macbook 2Ghz w/2 GB ram often, not always crawls and I mean really crawls. I got the most ram I could and my iBook 1Ghz w/ 1GB ram finshes opening most pages twice as fast as my new macbook. I'm so depressed and can't figure it out. My set up is wireless to a D-Link 614+ router then a SpeedStream5100 modem w/ At&t/Yahoo DSL. I also use WEP encription, but have been with no issues. I know when it's opening a page properly when watching the modem activity light. When it lights immediately after I select a link/site the browser is lightning fast to open the page. But OFTEN, I click, and wait sometime 15-20 seconds before I see the light or the browser budges. Almost like it's negotiating something before even trying to move. Horrible, very difficult to surf. Don't know if I need to change settings, if I may have a bad airport card or what. I plan on selling the iBook to help pay for the new macbook, but as of now, it's way easier and smoother than the new.
Believe me, ANY help or suggestions are soooo appreciated.