I have one last question..I have also heard that the third pci-express x16 slot into which I would plug in the second graphics card for crossfire of x16/x16 speeds, will get reduced to x8 and hence a x16/x8 crossfire would result..please clarify?
(Note 2) For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16_1 slot; if you are installing two PCI Express graphics cards, it is recommended that you install them in the PCIEX16_1 and PCIEX16_2 slots.
(Note 3) The PCIEX8_1 and PCIEX8_2 slots share bandwidth with the PCIEX16_1 and PCIEX16_2 slots espectively. When PCIEX8_1 is populated with an expansion card, the PCIEX16_1 slot will operate at up to x8 mode; when PCIEX8_2 is populated with an expansion card, the PC IEX16_2 slot will operate at up to x8 mode.
I interpret this to mean you have 4 available slots for video cards. Slot 1 & 3 are X16. Slot 2 & 4 are X8. Slot 1 shares bandwidth with slot 2 (AKA PCIEX8_1). Slot 3 shares bandwidth with slot 4 (AKA PCIEX8_2). If you leave slots 2 & 4 empty both slots 1 & 3 won't have to share bandwidth with any other slot(s) and should maintain X16 each. Which is why Gigabyte recommends installing 2 cards in slots 1 & 3. This way you will have X16 + X16.
I can also guarantee that in CF and using PCIEX16_1 and PCIEX16_2 slots (x16/x16) that nothing is being reduced and or lost. Right now if anything with one GPU you're under utilizing the X58's 32 Lanes of PCIe 2.0 to the GPU's. The HD 5870 only makes a dent on PCIe 2.0 at x8.
Things that are 'sharing' bandwidth are the: Marvell 9128, Gigabyte SATA2, and JMicron JMB362 and based upon your specs above turn them off (Disable in the BIOS).
YEP, Marvell 9128 is slower than the ICH10R if the Corsair Nova Series 2 are in RAID 0; see:
Marvell 9128 PCIe 2.0 x1 lane = 500MB/s max shared
Intel ICH10R not shared 300MB/s per port * 2 = 600MB/s.
I cant turn them off because the two 1 TB hard-disks are connected to the Gigabyte SATA2 ports and the Corsair Force 3 SATA 3 ssd is connected to the SATA3_0 port and since I have the modded FD14 bios I get very good speeds with the Marvell controller...also I use USB 3.0..
Now I want to know whether this is how things will work:
PCIEX16_1 and PCIEX16_3 will work as x16/x8 mode if I use Crossfire and USB 3.0 & SATA 3?
Why use anything other than PCIEX16_1 and PCIEX16_2 slots? CF unlike SLI can be on any PCIe slot if the card can fit it will work. Therefore, 'ideally' keep it x16/x16.
You are thinking it terms of Interface vs the reality of bandwidth of SATA, USB and GPU and forgetting actual bandwidth utilization. The only error I see is the choice of Marvell for SSD's in RAID 0. On PCIe here's an illuminating series of benchmarks with the latest and fastest MOBO's, CPU's and GPU's - http://www.techpowerup.com/reviews/Intel/Ivy_Bridge_PCI...
Again no doubt, the ICH10R is faster IF the SSD's are in RAID 0, a driver cannot add a PCIe 2.0 x1 lane. The later X58's e.g. G1's an OC models went to Marvell 9182 (no typo) which are PCIe 2.0 x2 or a maximum shared bandwidth of 1000MB/s. A single SSD by itself then yes the Marvell 9128 makes sense otherwise no. An 'Interface' has zip to do with speed or bandwidth. Example a SATA3 HDD vs SATA2 HDD, the mechanical HDD's can on their best day saturate a SATA1.
Thank u for all the advices....my question was incomplete..sorry for that..actually I wanted to ask that does the third PCI_E gets to x8 if USB 3.0 and sata 3 are enabled?
No nothing, gets reduced.
But as far as the Marvell 9128 Sata III ports go, don't use them for any raid they are crap! I know, my Sata III ports use the same crappy Marvell 9128 controller. The only thing I use those ports for are my optical drives.
And yes you will have a empty slot between your graphics cards to allow for better cooling.