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PCIe 2.0 x16 (4x mode) vs. PCIe 3.0 x16 for SLI

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August 31, 2012 12:36:47 AM

So on my sabertooth z77, I have three PCIe x16 slots. 2 PCIe 3.0 x16 slots, (dual @x8, single @x16) and one PCIe 2.0 x16 (4x).

I have my GTX 670 in the PCIe 3.0 x16 (I'm not sure if its x8 or x16) slot.

When I plan to SLI, space constraints in the case I am using (even though its a full tower) will prevent me from using the other PCIe 3.0 slot.

I understand the 4x mode has lower bandwith, allowing me less use of its capability.

How much reduced capability will I have with the second 670 in sli with it in the PCIe 2.0 slot?
a c 137 V Motherboard
August 31, 2012 4:20:08 AM

I'm trying to figure out how the second 3.0 slot won't work because of space constraints, but the 2.0 slot will? I don't quite get why that would be, unless the drive cage is in the way, but then, the first 3.0 slot shouldn't be able to be used either.

Regardless, you can't SLI with a card in the 2.0 slot with that board. The slot is only x4, and for SLI to work, the slot needs to run at x8 or better (an Nvidia requirement. The driver won't let you enable SLI if it detects that a card is in a x4 slot).
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August 31, 2012 5:23:41 AM

I have two PCIe x1 slots that I need. The first is covered by the H60 radiator, rendering it useless.

The second will be covered by the second gtx 670. The card is big, and it does take up two spaces instead of one.

This leaves me with one PCIe x1 slot, where my soundcard is priority. So, looks like the network adapter is going to have to go.

So I guess I did find space, but to some compromises.

Possibly to buy a PCIe x1 slot extender, and mount my network adapter somewhere else in the case?

Or get a USB Network Adapter?

Anyways here is a diagram to help you understand.

http://tinypic.com/view.php?pic=11cgux0&s=6

Here's my current setup.

http://tinypic.com/view.php?pic=26122hj&s=6
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a c 137 V Motherboard
August 31, 2012 5:31:24 AM

Yeah, I get ya now. Didn't need the diagrams, but very well done, anyway. :) 

I'm guessing you're talking about a wireless network adapter, right? In that case, yeah, I'd just go with a USB adapter.
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August 31, 2012 5:33:36 AM

Yeah, the problem is the h60 radiator attaches to the 120mm fan, and it has this plastic bottom piece where the hoses go out of. It just covers about 3/4 of the drive cage, not allowing me to put anything in that PCIe x1 slot.

The third PCIe x1 slot is going to be covered by the 2nd GPU, because the 670 covers two drive cages. If it was only one drive cage, sure, it would work, but unfortunately its not.

So, yeah, that's my dilema. Won't have to worry about it for now though. :p  Going to be a while until I get my 2nd 670.
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August 31, 2012 7:38:48 AM

Wait... I just thought about it... does a PCIe x1 card fit and work properly in a PCIe x16 slot?

I can just throw the internal network adapter at the bottom, the PCIe x16 (x4 mode) and everything should fit!
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August 31, 2012 7:57:35 AM

StefanSS123 said:
Wait... I just thought about it... does a PCIe x1 card fit and work properly in a PCIe x16 slot?

I can just throw the internal network adapter at the bottom, the PCIe x16 (x4 mode) and everything should fit!

YUP THATL WORK!
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