What a pity??I can not totally use my t5600(1.83G*2).I only can use cpu=1 to run 10.4.8.If i open multicore in bios,the mac will be slow in some applications.Do someone have the good idea to deal with this thing?To upgrade BIOS is the good choice?Does it work?Thanks!

done that for the dell D620 (a08 bios). didnt help. although dell says it fixes crucial intel microcode..

Yip - Same problem with my Dell E1705 - everything works great except the I can only run one core - I love OSX86 so much that I don't want to go back to Windows but it would be nice to use the power of the CPU, both cores, the whole reason why I purchased this laptop to start with was for the performance gain.