4-way SLI EVGA GTX 980 Ti CLASSIFIED

+salomoneliseo Your CPU only supports a maximum of 16 PCIe lanes, and only in the following PCI express configurations:

Up to 1x16, 2x8, 1x8+2x4

http://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz

Can 4 way SLI be done with this motherboard and CPU?

I'm not 100% sure, but I don't believe so. Your CPU only has 16 PCIe lanes, and since the general consensus is that GPUs like the 980 Ti, can come close to saturating x8 lanes via the card's x16 interconnect (port on the GPU that plugs into the PCIe slot), that would equate to 32x or 32 lanes for four graphics cards. The only thing that confuses the heck out of me is that Asus did indeed promote this motherboard as capable of doing 4 way SLI or CrossFire. But I know of no LGA 1150 CPU that can access beyond 16 PCIe lanes. If I were to take a wild guess, I'd wonder if they intended 3 way SLI plus a 4th card for PhysX.

Question #1: Did you connect the auxiliary six pin PCIe connector on the motherboard? Please view Linus video below at time index 6:20 min:sec to see location on motherboard.

Question #2: Do you have any "pcie cards or m.2 storage" installed? The reason that I'm repeating ak47jar3d's question, is that installation of such storage can disable a PCIe slot on certain boards. In my Asus X99 Sabertooth motherboard, this is indeed the case.

Linus: ASUS Z97-WS - As Good as it Gets IMO...
Time index: 6:20
https://www.youtube.com/watch?v=_UkIDk-lx6E

Asus Z97-WS manual
Jump to page: 177
http://dlcdnet.asus.com/pub/ASUS/mb/socket1150/Z97-WS/Manual&QVL/E9146_Z97_WS.pdf

Can 3 way SLI be done with respectable improvement?

My guess is no. Checking the Intel Ark page, it shows that configuration for 3 way SLI is x8 / 4x / 4x, even though the antiquated NewEgg listing shows the motherboard being capable of a max configuration of x8 / x8 / x8 / x8 (http://www.newegg.com/Product/Product.aspx?Item=N82E16813132126).

Intel Ark webpage for i7-4770
http://ark.intel.com/products/75122/Intel-Core-i7-4770-Processor-8M-Cache-up-to-3_90-GHz

What is the best way to accomplish 4 way SLI?

The best solution is to upgrade to an X99 chipset (LGA 2011v3 slot) motherboard and install a Haswell-E or Broadwell-E CPU.

i7-5930K (previous gen Haswell-E) cost $579.99 and $499.99 on NewEgg and MicroCenter (local pickup) respectively
http://www.newegg.com/Product/Product.aspx?Item=N82E16819117403&ignorebbr=1&cm_re=5930k-_-19-117-403-_-Product
http://www.microcenter.com/product/437204/Core_i7-5930K_35_GHz_LGA_2011-V3_Processor

i7-6850K (current gen Broadwell-E) cost $649.99 on NewEgg and MicroCenter (local pickup)
http://www.newegg.com/Product/Product.aspx?Item=N82E16819117647&ignorebbr=1&cm_re=6850k-_-19-117-647-_-Product

! Please note that even with a 40 PCIe lane CPU, you'll have two major performance hindrances: (1) Both 6 core CPUs will be bottlenecked while trying to serve data to four graphics cards. This is why professional hardware reviewers normally use Intel i7-5960X (Haswell-E 8-core extreme CPU) in their rest rigs during 3-way and 4-way reviews. (2) 3 and 4 way GPU configurations have horrific performance scaling. The only individuals that I know who build and maintain such configurations are those that do folding @ home or graphics rendering and exporting. But I'm sure this is not what you're trying to achieve because you wouldn't enable SLI for those purposes.

What would I do:

Honestly, I would sell 2 out of 4 of the 980 Ti's. I would place those two cards in the current Z97 motherboard and call it a day. I would take the proceeds from the sale and put in a safe place for when the 1080 Ti's come out. The proceeds should be enough to buy you one 1080 Ti at that time. Used price are falling in step with the discounted new 980 Ti's.


NewEgg sale on Ebay of new EVGA 980 Ti classified
US $409.99
http://www.ebay.com/itm/EVGA-GeForce-GTX-980-Ti-DirectX-12-06G-P4-0998-KR-6GB-384-Bit-GDDR5-PCI-Express-/291727190812?hash=item43ec4bab1c:g:TtAAAOSwh-1W5Ciy

NewEgg new EVGA 980 Ti classified
$459.99 after $30.00 rebate
http://www.newegg.com/Product/Product.aspx?Item=N82E16814487146

+Vellinious What exactly is PXL? I'd never heard of it before. From my google query below, my vague understanding is that the chip virtualizes the PCIe slots? Is that somewhat accurate?

google query: asus plx chip
google result:

https://rog.asus.com/forum/showthread.php?81623-Which-ASUS-boards-have-the-PLX-chip-for-16x16-GPU-s

"PLX" is a bit of a misnomer, PLX Technologies is (was) a manufacturer of circuit components like PCIe switches and PCIe bridges and PCIe multiplexers. What "PLX" or "PLX chip" means to most people is a chip which splices a single physical PCIe slot (or lane, or group of lanes) into more logical PCIe slots or lanes.

Short version is that it doesn't matter how many physical slots are mounted on the motherboard or how many lanes can be allocated in the BIOS because the processor can simultaneously address a maximum of 40 PCIe 3.0 lanes worth of bandwidth under best conditions. There are zero performance gains once PCIe 3.0 devices saturate all these lanes (in fact, there are minor performance losses since the PLX processing part adds signal latency and complicates timings, the increased signal traffic adds packet envelope overheads, and the increased signal collisions/errors require more packets get resent). So you might be able to install four GPU cards in a PLX x16/x16/x16/x16 configuration but actual performance will be comparable to (actually worse than) a non-PLX x16/x8/x8/x8 configuration. (And, besides, even mighty 980Ti and TitanX GPU cards at full load can hardly saturate >8 PCIe 3.0 lanes in practice, especially if they're directly interlinked off the PCIe bus with a CF/SLI bridge.) Just gotta wait for future Intel processors with more integrated PCIe 3.0 lane controllers. "

- by Korth (12-30-2015 08:54 AM)