I have an Asus X71SL with an Intel Dual Core T3200 processor. Any kernel version after 2.6.35-rc2 won't boot up on my machine without the nolapic kernel parameter at bootup. I have already reported this as a bug, but this is the only thing keeping me from updating to 10.10 or 11.04 when it'll be released.

Should I just use the nolapic parameter as a default and move on (and in the meantime try to resolve the bug) or is there a big performance/other trade-off?

  • I just noticed this problem as well. My Asus U46E (dual core i7) won't boot without the nolapic flag either (generic kernel of 11.10). It will boot with the flag, but only show 1 cpu. It is a bummer that half of the performance is wasted. Hope they can fix the bug sooner.
    – G. He
    Commented Mar 20, 2012 at 12:34

2 Answers 2


I don't think there are any limitations under that mode. All It will do Is make one of your processors work, not all of them. Basically, with nolapic it just uses one processor than the number installed.

  • I know the performance boost is not linear with number of cpus, but that still would be quite a performance drop, no? (I know this is better answered empirically, but I love to hear hard facts before that :) )
    – Cronco
    Commented Jan 19, 2011 at 21:28
  • 2
    So, a 50% performance hit. It might be possible that you could get the multiple cores working with a newer kernel, if you disabled hyper-threading in the BIOS, or tried other things like that.
    – Warren P
    Commented Jan 19, 2011 at 21:28
  • My BIOS is incredibly locked down, it won't let me change anything significant, except for boot order and password-protect the pc. I've been trying a lot of kernel versions, from 2.6.35-rc to the latest 2.6.37 in the kernel ppa. all have the same reaction.
    – Cronco
    Commented Jan 19, 2011 at 21:34

My machine is an Asus F50SF and the following helped:

  1. Open your BIOS settings
  2. Navigate to Security > I/O Interface security
  3. Change New interface card to LOCKED and save the settings.

Voilá! You can boot without nolapic and you can see all your cores.

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