We consider maximizing achievable information rate subject to a transmission mask constraint on power spectral density, with specific attention to two primary transmission strategies: faster than Nyquist (FTN) transmission and OFDM. OFDM is a mature PHY-layer technology, but there has been significant recent interest in faster than Nyquist transmission (see [1]), a single carrier approach that admits significant ISI rather than avoiding it, and for which attainment of the mask-constrained capacity is achievable, given sufficient receiver complexity and alphabet size at the transmitter. While FTN is theoretically interesting it's our view that traditional OFDM, with aggressive design, can more easily attain the capacity implied by the mask.