FreeBSD > 4.11 hardware issue with Asus PSCH-SR/SATA mobo

Hey.

I just went through a FreeBSD-related "hardware hell" session, but
let's not get into that. Let me explain my problem in its entirety.

My hardware: Asus PSCH-SR/SATA mobo. This is supposed to be made for
servers and has won many "awards", according to Asus. Nothing fancy
about it as far as I can tell.

(The CPU is a P4 and the HDD is a 10 k RPM WD Raptor through S-ATA.)

I bought the hardware and assembled it originally in an 1U rackserver
chassis over a year ago. Back then, I tried to install FreeBSD 5.x, as
it was the latest stable available. It wouldn't work on the box,
though. The FreeBSD boot screen just "wrote over" itself and the
previous text already on the screen (IRQ stats and that kind of ***).

So I installed 4.11. It WORKED! Now, 4.x is considered ancient, and I
have moved on to 6.x on my other box, and really, really don't wanna
run 4.x again.

So... my problem is that my hardware seems to be giving FreeBSD 5.x and
6.x issues, but not 4.x. I find this very weird.

Tonight, I updated to the latest BIOS version, tested default settings,
and even several altered configurations ("prioritze on-board VGA" and
stuff like that). No luck. Same god damn problem...

Let me explain exactly what happens in detail: The box boots, reads the
"bootonly" 6.1 CD inserted and starts outputting text... When the first
row is done, it doesn't "feed", but starts writing over the first
(bottom) line. Then, the entire "menu" screen (with the ASCII art
saying "FreeBSD") is outputted OVER the uncleared screen!

Now, you see underscores flashing around at fixed points on the screen,
and the CD is still reading, as if stuff is happening in the
background, only I can't see it. Pressing Enter doesn't do anything,
but I seem to be able to reboot still at this point by pressing Ctrl +
Alt + Delete.

(There is NOTHING wrong with the hardware monitor!)

Alright... I'm really worried now, and I really don't wanna run Linux
or any such crap. I have come to love FreeBSD and don't want to switch
to another Unix just because of some stupid hardware issue.

What can I do? I can't even afford new hardware, and that would be
pretty silly anyway, since this is STANDARD HARDWARE!

The 4.11 installation ran for almost a year without any problems
whatsoever.

I have probably forgotten to mention something, but I did my best
explaining my problem as exactly as I possibly could.

Any help is greatly appreciated.

.