Why aren't slots 1-4-7 used more for 3-way sli?

Toggle sidebar Toggle sidebar
E

embmicro

Reputable
Aug 27, 2014
1
0
4,510
I'm thinking about a new build where I may want to do 3-way sli. Right now I have two gtx770s in sli in slots 1-3 and the top card is 20c hotter than the bottom card under load (and running at a lower clock). This is with a fan blowing on them too.

It seems to me that its just a bad idea to sandwich cards together like most sli setups do. I've seen some motherboards that have the PCI slots to space cards with a slot in between with the cards in 1-4-7. However, it looks like this isn't common and most mobo manufactures don't include an sli bridge for that and want you to use 1-3-7 or 1-3-5.

This doesn't make sense to me. Why isn't 1-4-7 used more if you actually have space between the cards for a decent chance at cooling?
 
Solution
Damn_Rookie
To be fair there are surprisingly few Intel motherboards that support 3-way SLI (I'm less familiar with AMD boards), where each slot has a minimum of x8 lanes, as nVidia demands for it to be officially supported; with Intel you're limited to an LGA 2011 board or an 1150 board with a PLX chip.

Of the LGA 2011 boards that can run 3-way, but not 4-way SLI, the majority if them only have 6 expansion slots, so they can't run a 1-4-7 setup, and instead run 1-4-6.

Of the LGA2011 boards that can run 3-way, and can also run 4-way SLI, the needs of 4-way SLI dictate having x16 slots at the 1-3-5-7 positions. It's rare, but there are boards that have an additional slot at the 4 position, for example the EVGA X79 Dark...
Sort by date Sort by votes
clutchc

clutchc

Titan
Ambassador
Apr 22, 2009
43,150
411
131,790
I've asked that same question. Maybe it has to do with the way the copper trace pattern on the MB has to layout so as not to overlap or something. Or maybe because if the card was in the last slot, it would cover the FP wiring connectors at the edge of the MB.
 
Upvote 0 Downvote
Damn_Rookie

Damn_Rookie

Reputable
Feb 21, 2014
791
0
5,660
To be fair there are surprisingly few Intel motherboards that support 3-way SLI (I'm less familiar with AMD boards), where each slot has a minimum of x8 lanes, as nVidia demands for it to be officially supported; with Intel you're limited to an LGA 2011 board or an 1150 board with a PLX chip.

Of the LGA 2011 boards that can run 3-way, but not 4-way SLI, the majority if them only have 6 expansion slots, so they can't run a 1-4-7 setup, and instead run 1-4-6.

Of the LGA2011 boards that can run 3-way, and can also run 4-way SLI, the needs of 4-way SLI dictate having x16 slots at the 1-3-5-7 positions. It's rare, but there are boards that have an additional slot at the 4 position, for example the EVGA X79 Dark, which providing you don't have anything in the x4 slot, should run 3-way SLI in slots 1-4-7.

When it comes to the LGA 1150 boards that feature a PLX chip, that effectively increases the number of PCI-e lanes available for graphics cards, the same thing happens as with the LGA 2011 boards; being able to support a 4-way SLI setup, they have to have x16 slots in the 1-3-5-7 positions.

With the LGA 1150 boards with a PLX chip, the PLX is an expensive component, so while they could produce a motherboard with one that only supports 3-way SLI (in the 1-4-7 positions), I assume they must consider the potential market for one to be small, when you could get a similar board at a similar price that supports 4-way SLI.

I guess it all comes down to a combination of necessity when designing the boards, and the limited potential market for boards with the ideal 3 card setup (keep in mind the number of people running 3 card setups is very small indeed).
 
Upvote 0 Downvote
Solution
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom