Tri SLI: 16x/0x/8x/8x vs 8x/4x/4x

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UaVaj

Golden Member
Nov 16, 2012
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GPUs will be 680 Tri-SLI
CPU+ChipSet will be i7-3770K / Z77

does anyone know performance difference between

Z77+PLX motherboard (pcie 3.0 16x/0x/8x/8x) (i.e. GA-G1.Sniper 3)
vs
Z77 motherboard (pcie 3.0 8x/4x/4x) (i.e. GA-Z77X-UP4 TH)

thanks
 
Last edited:
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BallaTheFeared

Diamond Member
Nov 15, 2010
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You can't do Tri without a chip for added lanes on the mainstream platform last I checked.

e.g. GA-Z77X-UP4 TH would only do SLI, not sure about CF it doesn't seem to care as much about lane support.
 
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willomz

Senior member
Sep 12, 2012
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We've been through this on the PLX thread.

Tri-SLI is perfectly possible without PLX but you have 2 cards on a x4 connection.
 
Keysplayr

Keysplayr

Elite Member
Jan 16, 2003
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Would not recommend 4X for a modern graphics card. 8x or higher.
4X is fine say for a dedicated Nvidia GPU being used only for PhysX FYI.
 
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blackened23

Diamond Member
Jul 26, 2011
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UaVaj said:
GPUs will be 680 Tri-SLI
CPU+ChipSet will be i7-3770K / Z77

does anyone know performance difference between

Z77+PLX motherboard (pcie 3.0 16x/0x/8x/8x) (i.e. GA-G1.Sniper 3)
vs
Z77 motherboard (pcie 3.0 8x/4x/4x) (i.e. GA-Z77X-UP4 TH)

thanks
Click to expand...

I won't go into detail but if you want tri SLI, you want a PLX motherboard. Now personally, i'm not sure why you would opt for tri SLI as opposed to next gen dual SLI. Tri SLI doesn't always scale as reliably as dual SLI does, it is more variable. Whereas 2x SLI scales 99% of the time very well. But that's your own decision - you want a PLX motherboard in this case.
 
guskline

guskline

Diamond Member
Apr 17, 2006
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I have a similar comment. Why run 3 680s (expensive cards) on a motherboard that will not exploit their potential? Foolish waste of money.
 
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blackened23

Diamond Member
Jul 26, 2011
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guskline said:
I have a similar comment. Why run 3 680s (expensive cards) on a motherboard that will not exploit their potential? Foolish waste of money.
Click to expand...

Yes! Additional points:

-GTX 680 will have less resale value than next gen. Why not sell the 600s and get a next gen card?

-PLX motherboards aren't cheap. And at this point they don't have longevity or resale value, it is on the soon to be outdated Z77 platform.

-You can run tri SLI on some non PLX motherboards, but as a counter-point, very few non PLX motherboards have more than 2 full length PCIE slots, and you will run x8/x4/x4. Others have mentioned this, it isn't an ideal setup.

-Tri SLI isn't reliable in terms of scaling. Dual SLI is, dual SLI is nearly perfect IMHO. Scales in pretty much everything, reliably.

It's a personal decision. But when you weigh the opportunity costs, resale values, and longevity, I think that would tip the balance in favor of next gen dual SLI. Just IMHO :)
 
guskline

guskline

Diamond Member
Apr 17, 2006
5,338
476
126
UaVaj said:
GPUs will be 680 Tri-SLI
CPU+ChipSet will be i7-3770K / Z77

does anyone know performance difference between

Z77+PLX motherboard (pcie 3.0 16x/0x/8x/8x) (i.e. GA-G1.Sniper 3)
vs
Z77 motherboard (pcie 3.0 8x/4x/4x) (i.e. GA-Z77X-UP4 TH)

thanks
Click to expand...
You can see my specs for my 3770k below. I'm running 2 EVGA GTX670 FTWs in SLI and it is blazing fast. If I was running tri or quad I would opt for the LGA 2011 socket with a 3930.
 
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UaVaj

Golden Member
Nov 16, 2012
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if this was a new build from statch - definitely next gen sli (780) with IVB-E (i7-4930K) with X79 (socket 2011) - to wring out every bit of gpu performance.

-----

since this is reconfiguring - only part left to buy is the tri-sli motherboard.

Z77 (8x/4x/4x) for ~$150 - seem like a decent temporary solution (until IVB-E launches and further options become availlable).
vs
Z77+PLX (16x/0x/8x/8x) for ~$300 - for more permanent solution. $300 is IMHO alot to dump into a Z77 mb. at this price point - time to go X79.

-----

anyway found the answer. for those of you that may be in the same situation.

TechPowerUp PCIE 3.0 Scaling @ 5760x1080 for 680/7970

BF3 16x = 29.5 (680)
BF3 8x = 29.4 (680)
BF3 4x = 29.4 (680)
0% change

Crysis2 16x = 26.6 (680)
Crysis2 8x = 26.7 (680)
Crysis2 4x = 26.2 (680)
2% loss

Metro2033 16x = 15.4 (680)
Metro2033 8x = 15.6 (680)
Metro2033 4x = 15.7 (680)
0% change

Dirt2 16x = 95.5 (7970)
Dirt2 8x = 92.4 (7970)
Dirt2 4x = 86.4 (7970)
6% loss

WOW 16x = 74.4 (680)
WOW 8x = 73.9 (680)
WOW 4x = 69.2 (680)
6% loss

Heaven 2.0 16x = 27.2 (680)
Heaven 2.0 8x = 27.5 (680)
Heaven 2.0 4x = 26.8 (680)
3% loss

SC2 16x 1920x1200 = 113.7 (680)
SC2 8x 1920x1200 = 111.4 (680)
SC2 4x 1920x1200 = 115.8 (680)
4% gain

3DMark11 16x 2560x1080 = 7.9 (680)
3DMark11 8x 2560x1080 = 7.9 (680)
3DMark11 4x 2560x1080 = 7.9 (680)
0% change

with PCIE 3.0.
performance definitely takes a hit by dropping down to 4x, however the hit is manageable. given PLX has a 1-3% performance hit.
given a 680 gpu - it should be on par with either route.

anandtech also reports similar results with PCIE 3.0
 
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blackened23

Diamond Member
Jul 26, 2011
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If you're dead set on getting a PLX motherboard, I just don't understand why you would not go with LGA 2011. LGA 2011 is better for tri and quad SLI in every way, and doesn't necessitate a PLX chip. It has 32 native CPU lanes, and the cost between a PLX Z77 motherboard and a good LGA 2011 motherboard are roughly the same. Obviously, Z77 is going to be a dead platform soon while LGA 2011 will still have some life left, as it is compatible with the upcoming IB-E through a BIOS update.

It sounds like budget isn't a huge issue to you, I just don't understand why Z77, a dead platform (in a month) instead of LGA 2011?

EDIT: I just read your above post again and it sounds like you only need the motherboard. So the budget part isn't as significant as thought. Nevermind!.
 
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UNhooked

Golden Member
Jan 21, 2004
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I believe you need a min of 8x for an Nvidia card to work on that slot. The same limitation doesn't affect AMD
 
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BallaTheFeared

Diamond Member
Nov 15, 2010
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That's what I thought but I had no idea how it worked with 3.0

AFAIK it's only for Nvidia, AMD doesn't have that requirement.
 
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UaVaj

Golden Member
Nov 16, 2012
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Unhooked and Willomz - thanks for that necessary info.


Hurdles with NVIDIA and 3-Way SLI on Ivy Bridge

Users who have been keeping up to date with motherboard options on Z77 will understand that there are several ways in order to put three PCIe slots onto a motherboard. The majority of sub-$250 motherboards will use three PCIe slots in an PCIe 3.0 x8/x8 + PCIe 2.0 x4 arrangement (meaning x8/x8 from the CPU and x4 from the chipset), allowing either two-way SLI or three-way Crossfire. Some motherboards will use a different Ivy Bridge lane allocation option such that we have a PCIe 3.0 x8/x4/x4 layout, giving three-way Crossfire but only two-way SLI. In fact in this arrangement, fitting the final x4 with a sound/raid card disables two-way SLI entirely.
This is due to a not widely publicized requirement of SLI – it needs at least an x8 lane allocation in order to work (either PCIe 2.0 or 3.0). Anything less than this on any GPU and you will be denied in the software. So putting in that third card will cause the second lane to drop to x4, disabling two-way SLI. There are motherboards that have a switch to change to x8/x8 + x4 in this scenario, but we are still capped at two-way SLI.
The only way to go onto 3-way or 4-way SLI is via a PLX 8747 enabled motherboard, which greatly enhances the cost of a motherboard build. This should be kept in mind when dealing with the final results.
 
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willomz

Senior member
Sep 12, 2012
334
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It seems kinda weird that PCIe2.0 x8 is ok but PCIe3.0 x4 is not.
So it's not just about the bandwidth?
 
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