I have been wondering about how to use DCMs in a design lets say im doing some dsp filter design and I want my embedded multipliers to run as fast as possible. I synthesize my design using ISE or some other tool and my design synthesizes with a clock rate of say 75 mhz. Now lets say I add my DCMs and asychronous FIFO's to this design around the embedded multipliers. The thing that worries me is that i still have some delays in my clock signal, as well as in the data signals in my design. When I use the DCM, how do i know that the clock wont switch faster than the device can actually register? When designing something like this how do you know what is a safe multiplication factor so that all signals will behave as expected?
thanks