The JVM was very slow in the beginning because it was just an interpreter and had no JIT compilation. Then there also was the issue with 80bit floats on x86 mak

The JVM was very slow in the beginning because it was just an interpreter and had no JIT compilation. Then there also was the issue with 80bit floats on x86 making float computations slow, as the results of each operation needed to be saved back to memory to truncate them to 32/64 bit. The speed difference since those problems have been overcome has been relatively low. The biggest performance problem is garbage collection, which you can't overcome just with implementing ahead of time compilation. Another issue is the lack of SIMD support of JIT VMs.