Does anyone know what the PCIE lane population rules are for the X79 Classified? I checked the manual and could not find any information pertaining to this.
 
Thanks!

Considering he has an x1 sound card, I'm speculating he's asking what happens to the adjacent slots if an x1 is present in any one of them in terms of switching their configuration.   With 40 lanes from the CPU and 8 lanes from the chipset, I think it is best to stick such an option in the PCIe that routes off the southbridge, they'd have a constant speed regardless of the rest.  Looking at the X79 Classified visual guide, the middle x16 runs at a constant x4 while the one above it is a constant x8.  The other three x16 slots switch around.

randman76

EVGA_JacobF

Is this what you are looking for?

Sort of. Is there a specific config the cards need to be in for maximum PCIE bandwidth? Also, I thought for Tri-Sli you can get 16x/8x/16, at least according to Intel's chipset diagram. According to your diagram it can only work in x8/x8/x16. Doesn't this board have native 40 PCIE lanes?

 
I've asked that question before. I don't really understand why the board is unable to run at 16x/8x/16x when there are 40-lanes available. Unless some of those lanes are being allocated elsewhere.

According to Intel 16x/8x/16x is native and a lot of manufacturers (Asus for example)are taking advantange of that configuration. I don't understand why a motherboard which was designed to break records in benchmarking has such a limitation.

Exactly! You can also add the Asus Rampage Extreme IV to that list as well. I really hope that EVGA releases a BIOS which addresses this. For a flagship motherboard and the price we are paying we should be getting more. I guess all the extra $$$ we are paying is for all the gold content that's on the board. Honestly though, I would rather trade that for 4 more DIMM slots, a couple more SATA ports, and native 16x/8x/16.

Im really disappointed in this. I was really wanting to pull the trigger on a FTW board but now Im looking into other avenues. Would a bios update even fix this,or is it part of the board manufacturing?
 
 
Every other board I have looked at has been 16x16x8 for 3-way Sli.......

Just looked through the product specs on EVGA, and the PDF - it states, loosely:
 
PCI-E Slot Arrangement - 1x16, 2x16, 3x8
 
Doesn't exactly match the diagram Jacoc kindly posted above.  And I knew that was a mis-print when I ordered the board.  I think this is the first time we're seeing it in this thread.  
 
We were all assuming this board followed other X79 platform boards that it would have x16-x16-x8, such as the Gigabyte GA-X79 series (hated to list someone else, but Asus was listed above).   As you can see by my sig, I have spent a considerable amount on my rig and could really use the bandwidth.  Gaming, not so much as we know it doesn't really matter.  
 
As a matter of fact, I cannot find any other X79 board so far that does not support x16-x16-x8 3-way configuration.
 
Please let us know.  If there is a newer revision coming to correct this, I'm more than happy to return my Rev 1.0 board and await for the new one.

All I want to know definitively is where to put my PCI-E x1 sound card so my two graphics cards stay at x16.  

I would like to know as well but I do not think we will get an answer on this. This thread was created 4 days ago and so far no explanation from EVGA. If we do not get some kind of acknowledgement within the next couple of days I will RMA my board. The main reason why I was upgrading to the X79 chipset was for the ability to run 16x/16x/8x since it is a native function. But now, after I ordered the board and received it I find out that EVGA does not support that configuration. I should have realized that when I could not find the PCIE lane population rules in the manual. I am sure if they did publish that information there would have been far less purchases for their motherboards. Well, I had a good run with them. Started out with the 680i, 780i, 790i, 3-way classified, and the 4-way Classified. Sadly enough I do not think the X79 Classified will be staying on my list for long.

Ofcourse it matters. Its the principle of the thing. The X79 is supposed to be such an upgrade over the X58 yet it runs the same 16x8x8 in the 3 way as the X58. Its supposed to run 16x16x8 natively. And when it comes to CUDA apps there a major difference,theres also a difference in gaming. Depending on who you listen to it may not be but 1-5% but a difference nonetheless. Besides its EVGA.......a FTW board.....a record breaking motherboard maker. You would think they would want any advantage they could get.

It would be nice if EVGA could at least give an explanation for the reasoning behind limiting lane allocation to 32-lanes.
 
I also have interest in the SR-X. However, one of the major selling points for me is being able to access all 80-lanes from two processors via the PCI-E slots. I'm now concerned that only part of those lanes will be accessible.

lehpron

daleorama78
The X79 is supposed to be such an upgrade over the X58 yet it runs the same 16x8x8 in the 3 way as the X58.

1. It is the Sandy Bridge architecture in the LGA2011CPU that sets it apart from Gulftown/Bloomfield, if that didn't sell the system for you, nothing will. That said, I don't know if these first batches have a cold-bug or if people aren't utilizing variable strap ratios to explain the lack of +6GHz overclocks for personal WR's, but I'd like to hope that will change.
2. X58 had 36 lanes in the PCH yet only 32 were utilized, I don't remember too many complaints at the time. That said, it still took almost four years since the introduction of PCIe 2.0 standard for single-GPU graphics cards to reach 8 lanes worth of bandwidth, begining with GTX480, which is the equivalent of 4 lanes of PCIe 3.0. The controller in the LGA2011 CPUs is default 3.0, we're all just waiting for final certification while it operates at 2.0. 
3. My estimates are it will be another 2-3 years from now before future PCIe 3.0 single-GPU cards are reaching 8 lanes again, or fully saturating the 2.0 specification; meaning EVGA's 16-8-8 on their X79 won't be a hinderance until then (unless you pick up a dual-GPU card, but that's what dual x16's are for).  
4. Anyone with an X58 still has those 2-3 years before those future backward compatible 3.0 cards need more than the 32 equivalent 2.0 lanes in their dual x16's. It is assumed those with 3-way intentions have already moved onto X79.

daleorama78
Besides its EVGA.......a FTW board.....a record breaking motherboard maker.

This is why I see loyality as being over-rated, you put them up on a pedalstal based on whatever chance experiences of good quality and expect them to return the favor when they aren't obligated because they are a business and not part of your family. I suggest you ditch the fan/loyality BS and only focus on why you upgrade at all.  If you end up leaving EVGA for it, whoop-dee do.

daleorama78
You would think they would want any advantage they could get.

Note how giant SR-2 was compared to existing i5520 chipset dual-1366 boards, that's because EVGA attempted to satify as many customers as possible with features. Additional features cost money, how willing is anyone with the idea of paying extra to get EVGA to enable all 40 lanes in at least three usable x16 slots? I'm thinking very few, how do I figure? Because they sacrifice their desires to stay with EVGA, otherwise they would have moved on.

linuxrouter
I also have interest in the SR-X. However, one of the major selling points for me is being able to access all 80-lanes from two processors via the PCI-E slots. I'm now concerned that only part of those lanes will be accessible.

With respect, EVGA won't be the only dual-2011 maker, just the one that can overclock the pair of Xeons; thus weigh advantages with disadvantages and make a call.  The closest equivalents to SR-2 would be these two SuperMicro boards with 56-lanes and 68-lanes enabled with dual i5520 chipsets.  That said, with 36 lanes in each chipset, that's 72 total lanes not completely used by PCIe slots even on a regular GPGPU server board, so you guys can't just give EVGA a hard time. 

You completely missed the point........Every other board manufacturer used 32 also for the X58. Every other board manufacturer is using 40 lanes for the X79. Your point is moot.

Looking at the X79 FTW visual guide page 2:
 
Slot 1:   x8/x16 (switch)
Slot 2:   x1 (perm)
Slot 3:   x8 (perm)
Slot 4:   x4 (perm)
Slot 5:   x8/x16 (switch)
Slot 6:   x8 (perm)
 
I wonder if it is possible that slots 3 & 6 share bandwidth with 1 & 5 such that if they are populated, then they switch, thus 3-way SLI + PhysX as x8+x8+x8+x8.  But JacobF didn't cover 2-way + PhysX, so it should be possible using slot 4 for PhysX and maintain dual x16's.
 
Looking at the X79 Classified visual guide page 2:
 
Slot 1: x8/x16 (switch)
Slot 2: x1 (perm), same as FTW
Slot 3: x8 (perm), same as FTW
Slot 4: x4 (perm), same as FTW
Slot 5: x8/x16 (switch)
Slot 6: x8/x16 (switch)
 
JacobF says it 8-8-16 for 3-way SLi, so similar to FTW, then 1 is affected by 3 and 6 is affected by 5.  Except if nothing in 3 or 6, 1 and 5 remains x16.   If wanting 2-way SLi, must use slot 1 & 5.  Any other add-in PCIe like PhysX or audio must go in 2 or 4, otherwise you loose dual x16.
 
Looking at the X79 regular SLI visual guide page 2:
 
Slot 1: x8/x16 (switch)
Slot 2: nothing
Slot 3: x8/x16 (switch)
Slot 4: x1 (perm)
Slot 5: x8 (perm)
Slot 6: x1 (perm)
 
JacobF says up top that 3-way SLI will enabled 16-8-8, so why is the top slot 1 allowed to switch, shouldn't it be permanent x16?  Clearly a card occupying slot 5 affects slot 3.  So unlike FTW, 2-way + PhysX will loose dual x16's.
 

daleorama78
You completely missed the point........Every other board manufacturer used 32 also for the X58. Every other board manufacturer is using 40 lanes for the X79. Your point is moot.

I had a lot of points, don't generalize.  Quite frankly, when PCIe 3.0 gets certified, there is reason to worry about that because each x8 3.0 will function like x16 2.0.  Like I said, it will be several years before 3.0 spec graphics cards come to succeed 8 lanes, by then X79 will be dethoned.

Jacob just responded:
 
www.evga.com/forums/tm.aspx?high=&m=1377829&mpage=1#1377956
 
"It cannot be changed via BIOS [update]."
 
 

eduncan911
To run at PCI 3.0, you will need a PCI 3.0 graphics card.  So your point only applies to not one, but two future pieces of hardware and software releases.

So yes, there is a reason to worry - for those of us that have invested over $2200 in our 580s Hydros that are only, and will remain only, PCI 2.0 cards.  If a PCI 2.0 card is inserted into a PCI 3.0 slot, it will run at PCI 2.0 only.  So your "points" are muted unless addressing PCI 3.0 cards, which there are none ATM.

 
If the way I interpreted 2.0 x16 = 3.0 x8 was wrong in the sense that each slot would operate at x16 rather than the 8 lanes implied, then I apologize.  That said, did you expected older hardware to operate within a new standard that didn't exist at its creation?  That hasn't happened before.  USB 2.0 drives don't take advantage of USB 3.0 bandwidth.  I can't expect an SATA 3Gbps drive to run faster when plugged into an SATA 6Gbps socket.  Even PCIe 1.1 cards didn't operate 2.0 in a 2.0 slot.
 
It has been shown that even a GTX480 barely looses 2% on average in a 2.0 x8 slot, meaning even if you plug your $2200 worth of cards in all x8 slots and they operate at 2.0, you don't miss out much -- especially considering better boards with LGA2011 socket don't exist so everyone with Quad GTX580's will experience the same performance. 
 
You're definitely not getting four x16 because there aren't 64 lanes in the PCIe controller.    So unless you want to go back to an X58 with nF200's, you can't yet make the jump to X79 until nVidia decides to make a 3.0 revision, let's call it a "nF300 chipset" just to enabled four 2.0 x16's when you plug your cards in.