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Old 01-12-14, 05:52 AM   #9
MikeC's Avatar
Join Date: Jan 1997
Location: Virginia
Posts: 9,729
Default Re: Major System Upgrade

Originally Posted by wheeljack12 View Post
I was wondering, why does like hwinfo64 show your video cards running at pci-e 3.0 x16 (8gb/sec) at pci-e x16 (2.5gb) which is wrong. Pci-e 3.0 x16 should show (16gb/sec) period. I notice this in gpu-z also where it shows pci-e 3.0 x16 running at 1.1. Especially on a x79 mb. I know that both of your cards (gtx 780 ti) can and should run at full x16 speeds due to having 40 pci-e 3.0 lanes unless you one or two more x8 cards in there somewhere. The only thing I can think of is that you may have one of your cards in the x8 slots slowing down the bandwidth between them. Read below and check your manual on which slots are which:

(this is the layout of the x79-up4 mb)
2 x PCI Express x16 slots, running at x16 (PCIEX16_1, PCIEX16_2)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.

2 x PCI Express x16 slots, running at x8 (PCIEX8_1, PCIEX8_2)
* The PCIEX8_2 slot shares bandwidth with the PCIEX16_2 slot. When the PCIEX8_2 slot is populated, the PCIEX16_2 slot will operate at up to x8 mode.
(All PCI Express x16 slots conform to PCI Express 3.0 standard.)

2 x PCI Express x1 slots
(All PCI Express x1 slots conform to PCI Express 2.0 standard.)

1 x PCI slot

which leaves me with the question: do you have something in the x8 slots or do you have just two gtx 780 ti's on the mb?
No, there's nothing in the x8 slots, but I see your point in regards to hwinfo64 and gpu-z.

I also only have a single gtx 780 ti, which is installed in the topmost PCI Express x16 slot. The motherboard manual didn't include labels for the PCI Express slots.
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