Today’s complex PCB design CAD systems always include an essential Signal Integrity tool. These softwares offer a great account when designing a high speed digital system. The critical SI problems can be discovered before sending the design for a prototype run. It is important to know about the possibilities and limits of the simulators. A special PCB was designed to test these softwares and then compare the results with the measurements. One can find such traces on this Signal Integrity test board that will likely show up the weakness and possible faults of SI simulators. Simulations were done on the test board with HyperLynx from Mentor Graphics and PCB SI from Cadence. The simulation results were compared with measurements using an Oscilloscope and a Vector Network Analyzer.