Usually, MSP430 microcontrollers have a maximum recommended operating voltage of 3.6V, but the maximum rating is 4.1V. What is the problem of using a supply voltage between 3.6V and 4.1V?
The datasheets say:
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
In other words:
- going above the absolute maximum ratings might kill the device immediately; while
- going only above the recommended operating conditions might kill the device after some time.
In neither case is the device guaranteed to actually work; the difference is only how fast you get permanent damage.
"In theory" it will work, but in reality, when you consider noise & transients on the power supply (including those created by the device itself, as well as from other circuitry and external sources), and line-regulation & load-regulation performance of your voltage regulator, then operating any IC so close to its "Absolute Maximum Ratings" is a recipe for premature failure. Stick to the recommended Vcc range.