We analyze the modulation characteristics of the uncooled terahertz (THz) and infrared (IR) detectors using the variation of the density and effective temperature of the two-dimensional electron-hole plasma in uniform graphene layers (GLs) and perforated graphene layers (PGLs) due to the absorption of THz and IR radiation. The performance of the photodetectors (both the GL-photoresistor and the PGL-based barrier photodiodes) are compared. Their characteristics are also compared with the GL reverse-biased photodiodes. The obtained results allow to evaluate the ultimate modulation frequencies of these photodetectors and can be used for their optimization.