I shall present my problems and observations with the above distributions in order, but first I would like to say two things:
1) YMMV. I have read through some of the problems others have had
and how they overcame them on various mailing lists. It seems
that some of the problems I had were specific to my setup and
others did not have them at all on other motherboards or with
other video cards.
2) I did not spend all year testing each distribution. I was on a quest to get something on my Opteron that I can run my analysis software on, and compile my OSS on. I wish to use the Opteron due to its large cache and 64bit architecture. Having said that, I did not just install and say "eh, it does not work" and move on either. I at least tried to get each one working and looked for ways to overcome problems, being as I had already spent time putting the software on the machine.
Ok, here we go. Gentoo LiveCD 10-24-2003: this is the one I actually used the least, as I could not get X working at all, and wanted to move on. I will note however, that with the first Gentoo amd64 release that I picked up (not the liveCD) X worked, but no window managers would compile (less the built in one). It is worth mentioning that everything else worked, and worked well and fast. I would recommend this (actually the 11-09-2003 CD) for servers.
The second Gentoo LiveCD (11-09-2003) was no different from the first (IMHO). It seemed like everything works with the exception of the X, _however_ X would not even compile with this distribution. A little poking around the IRC channel and the bugzilla list did not seem to point to anything in particular, and people on the list said they had no idea. Others seemed to have it working but could not get the Radeon driver to work, while even more users said it worked fully. I received compile time errors on Xfree all over the place, too many for me to give a good diagnosis of. I gave up on this one and moved on. Again, other than that, it is using the 2.6.x line of kernels, all of my hardware was found (with the exception of the on board NIC, which no distribution of Linux can "see"), and it is quick. I recommend this for a server box.
Before I stuck in the Mandrake RC1 CD, I did have that funny smile on my face, knowing that since Mandrake beta1 worked so nicely with the exception of the "writing a large file to the drive lockup" that this was going to be the distribution. This was going to work, and work great. (sometimes I have a soft spot for Mandrake) This was not the case. The install would go smoothly for the first two steps and then tell me that there is a problem with my hard disk and that it needs to be wiped, and would I like to proceed? Odd. Telling it to move on and wipe the disk results in an error: "Can not format disk, drive error". I put in the Gentoo disk and fdisk the drive, no problems. I then partition the drive into three partitions (/boot, swap and /) so that Mandrake can have an easier time installing. Again, when I go to install Mandrake it tells me that the drive is corrupt/damaged/no space, and would I like to wipe/format it. I tell it yes, and then it tells me that there is a drive error. To make a long story short, I checked the drive, I even installed Fedora core 1 on it, and Mandrake still would not install. I even went so far as to try all possible hard disk access modes in the BIOS with no luck. Mandrake was no go. I decided to fall back on Mandrake beta1 and then see if I could upgrade. Mandrake beta1 had the exact same error. My conclusion is that the updated BIOS has some issue that Mandrake hates. Oddly, no other distribution exhibited this problem.
Suse 8.2 beta2 went well during install, and seemed to not have any problems. It did identify that there is an on board network controller on the ASUS, but could not do anything with it. After install I started to have the same problems that I had with Mandrake etc on the old setup, random lockups when writing huge files to/from the drive. Other than that problem, everything seemed to work ok, even X and KDE. Having seen that 9.0 was up on the ftp site, and having some time to install it, I decided to once again scrap the drive and try out Suse 9.0...
Suse 9.0 (what I am running now, and typing this on) was a fairly long install (due to my slow net access). The install took about two and a half hours to fully complete from start to finish.
I only encountered two problems with Suse, one of which is also present in some fashion in all other distributions with the exception of Gentoo: ACPI. In Suse (again, on this ASUS motherboard) unless you turn ACPI off (by going into failsafe on the install, or passing the acpi=off kernel argument) the kernel will fail to load completely. Slightly annoying. Secondly, during the install phase, it would not let me change the resolution on the video card (it was defaulted to 1024x768) and I wanted to change it before I "started the system". It is not a big deal, but made me wonder if anything else that I left default before would also have this problem. I am not sure, and after 2 hours of installing via ftp, I did not want to go back and find out. In Suse 9.0, KDE works, X works, and amazingly, OpenGL works. I have not noted this before, but no other distribution (which has had X working at least) has been able to do OpenGL on my ATI card. Xfree under Suse is using the "radeon" driver, but so was Mandrake and Red Hat 9.0 (original setup, with the FireGL installed). I make a second notation here in that the Nvidia also would not do OpenGL on any distribution (original setup). I was slightly pleased to see this. The only questionable aspect of the Suse distribution is the choice of kernel, which is 2.4.21. I know that 2.6.x is beta for now, but it does seem (from the Gentoo installs) that it is faster and able to play nice with the ACPI, unlike 2.4.x on this motherboard.
Some notes that may be of interest, that I have made along the way: Nvidia cards on these boards are very hard to setup, I suggest something else, or wait. Nvidia has new 64 bit compiled binaries on the Nvidia web site, but I have not tried them as my Nvidia card is now stuck in another machine. When installing on the Opteron which for now I think all motherboards use the Nforce3 chipset, pass two kernel parameters just to be safe: acpi=off and idebus=50 I found out by reading the source that the idebus option will not take a value greater than 50, but setting it to 50 is a LOT faster than the default 33MHz mode. If you have an all SCSI system, skip the idebus argument.