900mhz would be 10.5 x 86mhz = 903mhz. From what I know, you're chances of hitting this speed aren't very good but you might be able to achieve that speed as long as you have good cooling. If you read Celeron II reviews you'll generally find that not too many people had success in overclocking them. However, stuff could have changed (ie. the new 700's that were just recently produced could possibly be better overclockers than the first batches). Ultimately, it's just pure luck. You'll never know until you try it out.