With the increasing demand of Ovonic Threshold Switching (OTS) endurance performance, reliability acceleration model becomes imperative to speed up lifetime assessment. In this work, we develop a new ramp stress methodology to perform fast measurement with the proof of consistent lifetime and comparable distribution slope with respect to conventional time-consuming endurance tests. We have successfully proved material and polarity dependence of device endurance in GeCTe (GCT) based alloys thanks to this new method. This has been proved to largely reduce reliability evaluation time and provide a real time die-level reliability acceleration model for endurance prediction.