First, Unix does not use/require the bios table to read the drive parameters. Most all unix system read the drives directly. The FreeBSD kernel in 1998 the max cap was 8 gig, or some where around there. Now this is a Software raid. Meaning that parity bit and augth.. is all done by the cpu controlled by software variable or registers. V4 may make a difference over v3.4.807 but I dought it. It may be more to do with the motherboard revisions, Hardware changes.
If I had 4 300gig I could test with FreeBSD v6.1 and FreeNAS. But I only have 2 120's for spares.
That my 2 cents .........
ps. The user that had all the problem with (Seagate 7200.9) 4 x 300gig ended up configuring his unit as a 3 disk array with 1 hot spare.