never tried the Crucial, but i had an Apple store "Genius" send me to an online 3rd party vendor and i had nothing but trouble. i went back to apple and bought the Apple Samsung RAM and have had no problems. i complained to the guy and he said it may have had to do with having my original Samsung RAM in, along with the other stuff... i can't for the life of me understand why it should make a difference, but it did. as soon as i had all Samsung Apple RAM in my box it started working great. so, if you get the Crucial later and you start having problems right after that, try removing the original ram and see if it clears up. if not, put the original ram back in and take out the Crucial... and test it. do all this before warranty runs out... typically 90 days. i've only ever had problems with my macs when trying to skimp and get non-apple ram. in fact, as i type this i'm on my powerbook which i've carried across the US and back and forth across the Atlantic for a year and a half now and it still runs just as smooth as the day i bought it... smoother even since the Tiger OS.