Video card selection

[NerdLifeAMD]

Why is it so hard to find a motherboard that all the pcie slots are 16x ? is the full 16x bandwidth indeed needed for the cards to run well ?
if i got a motherboard with 4 pcie slots and two of them were 16 times one at 8x and one at 4x will the latter two cards not work well or at all?
if someone has a little knowledge of this a bit of clarification would be much appreciated

[Dirk Broer]

It is both not needed and in most cases won't be used as such either. While the slots are advertised as PCIe x16, they will seldom all be that at the same time once occupied.
There's a big chance that once both occupied the x16 slots will function at x8. Take as example the Gigabyte 990FXA-UD7.

It has
2 x PCI Express x16 slots, running at x16 (PCIEX16_1, PCIEX16_2) (Note 3)
2 x PCI Express x16 slots, running at x8 (PCIEX8_1, PCIEX8_2) (Note 4)
2 x PCI Express x16 slots, running at x4 (PCIEX4_1, PCIEX4_2)

(Note 3) 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 4) The PCIEX8_1 slot shares bandwidth with the PCIEX16_1 slot and the PCIEX8_2 slot with PCIEX16_2. The PCIEX16_1/PCIEX16_2 slot will operate at up to x8 mode when the PCIEX8_1/PCIEX8_2 is populated.

So installing four cards will have them run all four at x8.

Example of a pretty high-end mobo with lots of PCIe slots, the EVGA X79 Dark (up to six video cards)

[NerdLifeAMD]

thanks dirk

[Terry1953]

The problem I run into is putting them so close then cooling them.

[Dirk Broer]

The problem I run into is putting them so close then cooling them.

Watercooling seems the only solution to this problem, otherwise it's a row of three 140mm fans above your video cards...
The fact that most casings will stack your cards vertically doesn't help either .....

That's why I have my eyes on this: the Coolermaster HAF XB

[NeoGen]

That's why I have my eyes on this: the Coolermaster HAF XB

That is a monster sized box!!

[Terry1953]

That's why I have my eyes on this: the Coolermaster HAF XB

I like that one but I started using this one http://www.newegg.com/Product/Produc...82E16811146075 because of the massive amount of air I can push through it. I can put 7 120mm fans in it with one being right over my GPU's. And the fact that it only runs $40 with zero sharp edges like I find in so many cheap boxes.

[Dirk Broer]

As for massive amounts of cool air, able to be pushed around:

A Danger Den casing. They went out of business due to the recession. Their casings were REAL expensive....

[Dirk Broer]

That is a monster sized box!!

It is smaller than a Corsair Carbide Air 540, but it has a more thought-through placing of the motherboard, so that a multiple GPU setup does not require extra headaches. With two 140mm intakes, a 120mm exhaust and a 200mm top fan you can cool as much GPUs as you can fit on your board, as the mobo lies horizontally. And you can fit in a 240 or 280mm radiator to cool your GPUs and use a 120mm to cool your CPU when you are into watercooling. Enthusiasts even fit in extra radiators in the lower compartment!

[Dirk Broer]

That is a monster sized box!!

Managed to get one for just 60 Euro's! But it is indeed a big -mostly broad and deep- casing.

I think I will transplant my A6-3500 into it, so I can mod the casing where that APU sits in now.
(The same casing as my original Duron 650, and later my Athlon XP 2400+ sat in)