Comment by gjm11

What looks like the relevant table has a summary line saying "geometric mean: 1.45x" so I think that in this case "45% slower" means "times are 1.45x as long".

(I think I would generally use "x% slower" to mean "slower by a factor of 1+x/100", and "x% faster" to mean "faster by a factor of 1+x/100", so "x% slower" and "x% faster" are not inverses, you can perfectly well be 300% faster or 300% slower, etc. I less confidently think that this is how most people use such language.)