I just installed Xubuntu 12.04.3 on my Toshiba Satellite, and I've noticed that Chromium is REALLY slow. I have a 3 bar WiFi signal, so it can't be that. Also, when the computer ran Windows, it actually got faster internet. Is there a way to get faster internet?
When you say your internet is slow, are you refering to the actual speed you're obtaining from your isp or it just appears to be running slowly? If you run a speedtest from speedtest.net and compare it to what you're paying for from your ISP and it is a major difference, I'd check that your network adapter's are up to date driver-wise.
If Chromium is the only browser running slow I would suggest uninstalling it and trying a fresh install.