What happens when you stress the system? Your particular CPU base clock is supposed to be 2.5Ghz, but has a "Turbo" mode will speed up the CPU to 3.5 Ghz(3.7 in your case from Dell) under certain loads depending on how many cores are being utilized. If you run something like CPU-Z while running something processor intensive, you'll see the CPU speed increase to where it should be. You should be fine.