If you're sure that the C1 and D1 steppings refer to the *same design*, then I would expect it to work in theory. In practice, you will be boosting the power consumption and heat generation by 25% or so, and the power circuitry and/or CPU cooler in your computer may not be able to handle the increase.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.