I have an IBM ServeRAID M5014 RAID card, it uses PCI-E 2.0 x8. Although I am only going to be using four SATA HDDs in it in RAID5, so it will not be operating at anywhere near capacity.
I am planning to put it in a gaming rig which I am still finalizing the hardware on although I have decided to go with an i7 3770K CPU. So far my motherboard choices are between the ASUS Sabertooth Z77 and ASUS P8Z77-V Deluxe based on the OCT 2012 motherboard review on this site.
The main reason I am also considering the deluxe is because that is a server-class RAID card (Even though its a re-branded LSI) and is somewhat picky about what desktop motherboards it will work in (Namely, it's only officially supported in for IBM servers). I know that it will work on nearly any P8Z77 line ASUS board, but although the Sabertooth is a Z77 board, I don't know if it counts as a P8 line model. (Personally, I like the Sabretooth more than the Deluxe, not to mention its much cheaper.)
On top of that, since this will be a gaming rig, I am a bit worried about the fact that I am going to be forced to either make the RAID or 3D card operate at below it's specs. Both motherboards have two PCI-E 3.0 x16 ports, but they only operate at x8 if both are used at once. Not a problem for the RAID card, but this would make my 3D card suffer (although I have no idea by how much, I am still researching which 3D card to choose, it will likely be a GTX model though).
The Deluxe however has an additional PCI-e 2.0 x4 port, which would let me use the 3D card at a full x16 lanes but then my RAID card suffers at x4 lanes instead of x8. And although as I said before I am not operating it at anywhere near capacity (its meant to work with up to 32 SAS drives, and I am only using it with a SAS to SATA breakout cable for four) I am worried that I am already basically jury-rigging a server card to work on a motherboard its not supposed to, and that putting it on a x4 slot instead of x8 is asking for trouble.
I know this is a pretty unorthodox question, but does anyone have any advice?