Intel Celeron G5900 + Pentium Gold G6400 Benchmarks - Low-Price Comet Lake CPUs
The Celeron G5900 performance at $42 in particular is especially in tough shape against the Athlon 3000G at $49.
Any of these very low-end CPUs are particularly poor for code compilation.
In some of the cases, the Core i5 2500K Sandy Bridge available via used channels is noticeably faster still than the Pentium Gold G6400.
The results aren't too bad for single-threaded applications that do not make use of AVX.