Performance of lateral phase change memories (LPCMs) is investigated by both electrical characterization and finite element analysis. Ge2Sb2Te5 lateral PCMs (GST-LPCMs) exhibit a low reset current but a bad endurance. By replacing GST with Sb2Te3 (ST) and adding a TiN layer between ST and electrodes, the ST-TiN-LPCMs are demonstrated to have a much improved endurance. Finite element analysis of the LPCMs with electric-thermal structural interaction shows that thermal confinement makes GST-LPCMs low-power consumptive but that high level stress makes them readily broken. In contrast, ST-TiN-LPCMs experience low level stress during operation but high power consumption is required.