Render slowdown ??? 2.40 ??

Im running windows xp 512 ram, running 2 threads , no osa using unified render it is taking 54 seconds to render a plain black backround, in fact all of my renders are much slower then before, but my renders with 2.37 go normally (fast)…like they always did but everything with 2.40 seems really slow. Is anyone else having this problem ??

I’ve seen some reports on this. Do a search and you’ll find several posts about it and how to solve it