Tone Reservation (TR) is a method of Peak to Average Power Ratio (PAPR) reduction in Orthogonal Frequency Division Multiplexing (OFDM) system. In this paper, we present the importance of considering an improved model of the power amplifier (PA) to evaluate accurately the performance of TR method based on Conjugate-Gradient algorithm. Simulation results are performed using the WLAN IEEE 802.11a standard in presence of two memoryless models and nonlinear polynomial model with memory. These models have been obtained by experimental study including measurements and parameters identification with a 2.4GHz class AB PA from RF Micro Devices. The evaluation results and the experimental comparison show that TR method improves transmission quality, in terms of Bit Error Rate (BER) and Error Vector Magnitude (EVM) and that it is useful to take into account memory effects in PA modeling.