Hello, I just had a dell Xps 8100 warranty replaced with a XPS 8300 the only noticable difference is the graphics card. It originally had a nvidia geforce gts240 but the new one has a ati radeon hd 5450 1gb ddr3 Upgrade or downgrade?
The GT 240 and the HD 5670 are roughly equal in terms of gaming performance. They downgraded you from a mainstream video card to an entry level video card. The HD 5450 is good if you are only going to watch videos.
I would suggest you speak to Dell support regarding that issue... and maybe request to have them ship you another GT 240 while you ship them back the HD 5450 at their expense.