4GB RAM slows down ubuntu

[femi71 at web.de]

Hi,

yesterday i installed kubuntu in order to get rid of a silly problem: When i add 1GB RAM (3x 1GB are already inserted), Suse 10.1 got very very slow. Booting Windows or Knoppix makes no problem with 4GB. Now after installing kubuntu with kernel 2.6.24-24-generic the problem is the same: 3GB are ok, 4GB slow down the system dramatically (2, 3 times slower). At a certain point during booting, the moving bar stucks. Where can i search for the problem?

It is a ASUS P4P800 SE Mainboard.
RAM is said to be supported,
the BIOS recognises it (it says 3,7GB but this is documented in the manual), even in dual channel mode.
RAM is ok and all 1GB bar fit together. (memtest gives no errors.)
again; Windows XP (and Knoppix) has no problems, (Knoppix is a bit slow as it is running from CD, therefore i wouldn't  swear that it is not slower.)

Is this a known bug or has someone an idea for a solution?

Thanks,

Günther


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