Public bug reported:
I have a P4 1GB system. Part of the memory is shared with the built-in AGP card. The BIOS is setup to have a 32MB AGP Aperture. Problem: When the Memory Allocated to the AGP Card is 16MB (lower than the aperture setting) Ubuntu is very sluggish, like it takes 5 whole minutes to boot up. But: (1) When the shared memory is at 32MB, Ubuntu is very fast -- 30 seconds from boot to KDM login screen. (2) When shared memory is at 16MB and kernel parameter mem=992M is used, Ubuntu is fast. But when mem=1008M is used, performance goes back to "snail" mode. (3) When using latest available Dapper kernel source (Package Linux-Source-2.6.15), compiled without highmem support, performance is fast. And: (1) Problem not encountered with Windows XP (with 32MB aperture and 16MB shared memory) (2) Problem have been tested to latest available kernels from Breezy, Dapper, and even, Edgy. Not really a big problem, but should this behavior, once confirmed, should be documented somewhere. There's a lot of people complaining about slow performance in ubuntuforums.org, this may be one of the culprit. ** Affects: Ubuntu Importance: Untriaged Status: Unconfirmed -- slow overall performance (because of highmem support and/or AGP settings?) https://launchpad.net/bugs/54635 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs