I compiled a branch and bound program to test this. Results for a 30x30 symmetric matrix processed using exact same code for both engines: NodeJS: ~20 seconds

I compiled a branch and bound program to test this. Results for a 30x30 symmetric matrix processed using exact same code for both engines: NodeJS: ~20 seconds QuickJS: ~200 seconds So, from a single experiment QuickJS seems about 10x slower than NodeJS for this particular use case.