MacPro 3,1 (2008) logic board SAS connector: Has anyone "replaced" the stock hard drive backplane? I have a lightly hot-rodded, early 2008 MacPro 3,1. Boots from an SSD mounted in the lower optical bay and attached to the second optical SATA port. Each of the four internal drive bays hosts a 3TB drive which I have configured as a striped and mirrored ZFS partition. Unfortunately, all my 2012 drives are running at 2008 speeds and are limited to 3 GB/s.

Looking for insight from anyone who has replaced the stock hard drive subsystem to 6GB/s speeds via a 4 or 8 channel PCIe SAS/SATA card with an internal SAS connector and connecting it to the built-in SATA backplane with an "extension" cable.

My workflow is predominantly InDesign, Illustrator and Photoshop with light video editing occasionally tossed into the mix. My typical "large" Photoshop files range from 200MB to 600MB. Most InDesign files are 100 to 200 pages in length with transparency, layers and multiple elements on each page.

I'm not looking for ideas surrounding Apple's RAID card that sits in the topmost slot. I'd rather use the stock backplane since I can plug directly into it.

For anyone posting, I'd appreciate suggestions on a SAS card for the upgrade. It needs a minimum of a single internal mini-SAS port, but dual internal ports would be welcomed (for attaching the boot SSD). Since I'm running ZFS I dont need hardware RAID support. Just need to talk to the bare drives. Lack of boot ability means I only run the backplane and keep the SSD on the motherboard. 

While increasing speed is my main intent, I don't want to sacrifice system stability or data integrity.
For changing the back plane you might look at the Pro Cable 1 with a review here.

There is also the DX 4 if you want to really stuff you Mac Pro with drives.

I don't have direct experience with a controller but was leaning toward a MAXPower RAID mini-SAS 6G-1e1i since it has both internal &amp; external SAS ports.  Note that this card will not boot the Mac Pro.

The real problem is that I would want both a RAID card and a Mercury Accelsior and the Mac Pro (2008) only has 1 free x16 PCI 2.0 slot and you would need 2.

There is also a rumor of a Mercury Accelsior with eSATA ports in the near future.