FWIW - I ran into this problem as well using these cards with Unraid 4.5 (release). I was upgrading the MB and controllers because I was sick of the I/O limits of using the 8 port promise PCI SATA controller cards. The MB was a GIGABYTE GA-EP45-UD3P, and the controllers were the SYBA SY-PEX40008 4 port, 1x PCIe cards. I currently have 14 drives, so 8 ports on the MB plus 8 from the 2 controllers covers me.
I had similar hang problems as those described on this thread. The BIOS in the cards could always recognize the drives, but if you had any drive connected to one of the SYBA cards, linux would hang as soon as the Sil3124 driver touched the physical disk. The drive active light would come on and the entire system would become unresponsive.
I tried
+ Switching to the base (non-raid) bios; no help.
+ Booting with and without dives connected to the 2 different MB controllers, and no drives connected to the SYBA cards; no problems at all.
+ Booting with and without dives connected to the 2 different MB controllers, and 1 or more drives connected to each of the SYBA controllers; always hangs on the first disk recognized by the kernel driver.
+ Moving the cards to the different 1x PCIe slots, running with both or only one. Any time a drive was connected, it hung, otherwise no problems.
SYBA BIOS always recognized any drive I attached, new or old, raid bios or non-raid.
Finally, I stuck a disk with windows on it and booted; windows seemed to be OK with the syba controllers; once I finally managed to convince it to install the drivers (more of a PITA than it should be ideally).
In the end, my conclusion was driver trouble in the current version of the kernel build, so I returned the cards to newegg.
There is a bright side to the story, however. Looking for replacements, I found the Adaptec 2241000-R; which newegg had available as an open box special for only $6 more than the SYBA cards. Even better they are PCIe 4x. Even better still, they work in the GB mobo, which apparently has trouble with PCIe 1x cards in its PCIe 16x slots (which GB claims are for video only; see discussion here http://lime-technology.com/forum/index.php?topic=3739.0)
Cards seem to be good. IO bottlenecks are a thing of the past; 10.5 TB usable storage and 60MB/s parity checks instead of 10, I'm happy