Testing at-speed delay defects is difficult on a speed constrained low cost tester. This paper describes the use of a clock chopper based onproduct clocking circuitry and interfaces to delay ATPG to achieve reliable test patterns. We also describe the test compression methods used to address the problem of increased test data volume due to delay tests. Data is presented on several industrial circuits to demonstrate the effectiveness of these DFT methods on nanometer designs. Our results show that a seamless combination of atspeed delay testing with compression can help to test the nanometer defects at a very competitive cost.