my new computer seems so slow?

I purchased a new Dell Studio XPS. I had an emachines which ran windows XP. Why does my NEW computer run so slow? It shows that windows is installing updates. Could that be making it run slower than it should? I have dial up (only thing offered where I live) and it is slow already, but I was told this new computer with a “quad-processor” would work 4 times faster than my old computer. That doesn’t seem the case at all – in fact, it is actually slower. How can this be? Is Windows 7 slower if you operate it with a dial up internet connection?