I have been using ddr_stress_tester tools for many years, this year, I found the tool cannot work well on some newer manufacturing process DDRs, (20nm or 25nm DDRs), we found that the binary will hang when I select cpu frequency. For example, winbond w631gu6rb and ISSI IS43TR166640C-125JBLI-TR. by the way CPU model is mx6solo/dl