I had a 433SPMW that wouldn't prime at 2.4 GHZ. I dont see what the big deal is with them, they are still as unconsistent a week as any other AMD64. I managed 2.5 GHZ (278 x 9 1:1) @ 1.6 with my week 437 3500+.
Here is a pic of the CPU before I sold it.
http://www.3dxtreme.net/other/IMG_0098.jpg