You are prevented from overclocking by Dell - also the nature of the machine (workstation) where stability is as high of (or even higher) priority as performance. The options in BIOS that would allow overclocking are locked to prevent unintentional damage to the system. There are options though such as overclocking programs (software) that may be able to get you a few more MHz's out of the CPU(s) and there is the (somewhat risky) option of modding your BIOS to unlock it. I'm thinking for a workstation class machine it's very unlikely a modded BIOS already exists.