couple of stupid questions about SLI

[Trik'Stari]

Ok, I have a couple of stupid questions concerning SLI.

 

1. What is the minimum number of expansion slots for a case to have for it to support quad SLI?

 

2. Is there any dual sli motherboard with a plx chip to allow both cards to run in x16 mode? (meaning a board with a plx chip that only has room for 2 or 3 gpu's at most, the ones with room for more cost alot more from what I can see)

 

I ask the second question just out of curiosity, I know the top end boards with plx chips (or lga 2011) can run 2 cards in x16x16 mode, What I don't understand is why there doesn't seem to be a dual SLI motherboard that offers this as well. from what I've read it doesn't really make a difference, but it would still seem like a price point they manufacturers have missed.

 

Think about it, a "dual sli" purpose motherboard (like all the ones with three x16 size slots) but with a plx chip allowing both cards to run in x16x16 instead of x8x8, but without the mega sized price of boards that can run x8x8x8x8.

 

Anyways just noob questions generally. I just find it a bit odd that some of these dual sli motherboards advertise themselves as having "extreme multi graphics support" and yet when hooked up with multiple cards, your using only half of what you paid for. I just haven't seen a board like this and it seems like an option they missed.

[WinNut]

Answers

 

1. 8
2. no

[Trik'Stari]

Thank you @WinNut

 

Seems kinda stupid on the manufacturers part. What about on x79 boards?

[kingdorian]

Thank you @WinNut

 

Seems kinda stupid on the manufacturers part. What about on x79 boards?

It might seem stupid, but  I remember reading somewhere the performance loss between running in x8 and x16 mode is less then 2% in most cases, so even a 780Ti or a 290x won't be bottlenecked by running "only" at x8. x8 on pci-e 3.0 is by the way the same as running x16 on pci-e 2.0. 

What you can do if you have a decent gpu in your system, 3dmark it. Put it in a x8 slot and 3dmark it again. If everything is correct the scores should be about the same.

[WinNut]

Thank you @WinNut

 

Seems kinda stupid on the manufacturers part. What about on x79 boards?

X79 doesn't even need it, natively the CPU gives off 40 PCI-E lanes so it can run in x16/x16 or x16/x16/x8 or in x16/x8/x8/x8 without a PLX bridge chip.

[Trik'Stari]

@WinNut I was asking if there was an lga 2011 board that is the equivalent to the type of z87/97 boards im talking about, the low to mid 200$ range that has "gaming" and "sli" all over the place lol

 

And I've read before that the difference between running a top end card a x8 and x16 us negligible, I for one find that vary hard to believe since your cutting the bandwidth in half, but people who know more than me say it so :\. It's really just an issue for me because as a consumer I feel like if I pay for something, I damned well better be using all of it. Guess that's just me lol.

 

What kind of results would a person get from running four Nvidia GTX660's in sli together? I have one EVGA gtx660 2 gig ftw edition and I'm wondering what kind of performance I would get if I bought 3 more as opposed to upgrading to a better card (when I build my first intel system, whenever that is lol, hopefully I'll have the money to get started when the x99's drop)

[totjup5]

Thank you @WinNut

 

Seems kinda stupid on the manufacturers part. What about on x79 boards?

I don't know any boards on the intel side, but my 990fx board runs both of my cards in 16x mode.

[Faa]

A board with a PLX chip like a maximus v extreme just adds 16 1.0 lanes. So basically it turns 4x/4x/4x/4x to 8x/8x/8x/8x. Depends how flexible the PLX chip is, I managed to get a card running at pci express 3.0 at 16x with a 2600K which has pcie 2.0 controller (proof: http://i.imgur.com/QmdK8BD.jpg).

Normally it should be 8x/8x but since a plx chip can add 16 lanes it should turn it to 16x/16x