its not faster and the accuracy improvement is more of a curiosity than of real value. infact on modern desktop/console hardware invsqrt hack is really bad. it

its not faster and the accuracy improvement is more of a curiosity than of real value. infact on modern desktop/console hardware invsqrt hack is really bad. it causes type aliasing which is 'expensive' in native software terms. the x86(-64) chips underlying them all now has a dedicated instruction for this, as do the PPCs that came in the generation before... still of value on ARM though which is becoming more and more important.