8X RAID in 16X Slot

So, I brought this up in another forum but didn't really get anywhere.

I'm building a Home Storage Sever and want to go with RAID5 (5x3TB)

I've been looking around and decided the ntel RAID Storage Controller RS2WC080 seems to offer the best band for the buck and in RAID5. I plan to use a Pentium G860 and now I need a board to go with this processor that will also work with said RAID card. Most LGA1155 boards have 1X, 2X, 4X and 16X slots but it's mostly only expensive server boards that have 8X slots. I've ready that lots of boards don't like to have anything but video cards in their 16X slots. I was also told that you need a board that supports SGPIO which confuses me because it was my understanding that SGPIO communicates with the backplane and is not decessary if you're connecting direct to harddrives and not to a backplane.

Can anyone clear all of this up?

You should be fine with any LGA1155 board and using it in the 16x slot. What some boards may not support is booting from a hard drive in a RAID card. If you're booting off a motherboard hard drive, you should be fine.

Then again, I don't know much about RAID cards, so I'm just going off some assumptions.

Consumer boards, especially some ASUS models can be notoriously finicky with PCIe HBA's (Especially when they are placed in the only PCIe x 16 slot). Another thing to consider is that PCIe slots are different physically and electrically. You can have a 16x slot on your motherboard that only does 2x, or 4x electrically. Your card will still work but may perform slower than you expect. If you want guaranteed compatibility, buy a real server board.

The size of the PCIe isn't really the main problem, but rather that some motherboards have non standard additions to the PCIe bus allowing to route PCIe lanes dynamically depending on the ports used, overclocking, etc. Also, some lack some kind of memory that means RAID cards/HBA don't work. So the idea is to get a tested combination or go for a professional board, and avoid enthusiasts boards.

I think I'm going to just get a Supermicro MBD-X9SCL-F-O

SuperMicro is a save bet, as long as it is not a HP SmartArray controller which gave me lots of headache with a X9SCM-F in the past

I've used some Intel SASUC8i's (LSI 1068e/B3) on several boards from Asus and Gigabyte as well as SuperMicro an these x8 cards always worked fine on the PCIe "x16" slots. But I agree with mwroobel, they cheat with dynamic lanes - so be sure it really has x8 lanes for the best performance.

Do you need a microATX board ? Personally I'm about to order a X9SAE-V to go with a Celeron G1610.

Check your motherboards documentation, they should have it spelled out.

I didn't at first and had my GTX 680 in the first PCIe x16 slot, works perfectly.

I then had my LIS 9260-4i in the second PCIe x16 slot. I didn't realize I was hampering the video card until I checked in GPU-Z and it showed my card running in x8 mode.

What happens is the PCIe Controller autmatically drops the mode down to x8 because it is assuming you are adding a second video card to do SLI or Crossfire.

I moved my RAID card down to the 3rd PCIe x16 slot and that fixed my video card.

The Raid card I have only requires a x4 PCIe slot and since the 3rd PCIe slot is x4 this worked out perfect.

Page 2-12 of the Asus Z77 Sabertooth motherboard for reference.

Most other 1155 boards will probably be similar.

Hopefully this helps.

@sawk: While it sounds like a huge performance drop, the switch from x16 to x8 has nearly no effect to the graphic performance as Linus Sebastian (NCIX Tech Tipps) has shown in one of his YouTube videos. As far as I remember it was this one: https://www.youtube.com/watch?v=vfXALgE7mVM

However, for a controller, the impact is for sure more "feelable" (is this even a word?)