For pre-synthesis, try Verilator (converts your Verilog module into a C++ class - super cool for cosimulation) or Icarus Verilog (takes traditional Verilog Test

For pre-synthesis, try Verilator (converts your Verilog module into a C++ class - super cool for cosimulation) or Icarus Verilog (takes traditional Verilog Testbenches). They both can emit VCD waveform trace files that you can then analyze using GTKWave. I have never heard of a simulator being less accurate than hardware, unless we're talking about very obscure bugs (and those are mostly limited to UI bugs).