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PCI-E Dual x16 vs. x16/x8 nVidia SLI. Help Please!

I am looking at upgrading the Mobo and CPU in my current rig. I want a Mobo that will support future processors for future upgrades and have decided to go with the Intel 1155 socket. My current specs are:

Custom built by myself:
Windows 7 Ultimate x64 SP1
Corsair White Graphite 600T
MSI P43-C51 MS-7519 v2.1 Socket 775
Intel Core 2 Quad Q9550 2.83GHz
EVGA GeForce GTX 460 SC
Corsair Professional Series Gold AX850 PSU
16Gb Corsair Dominator 1333 (4x4GB Quad Channel Kit)
Corsair Airflow Memory cooler (packed with Quad Kit)
Corsair H100 Liquid cooler on CPU (4 fans in push/pull config

I want to keep everything except the Mobo, CPU and Video Card. I am doing this on a slight budget. I want a better Mobo and Video cards to start with. And a CPU I can OC and then upgrade later when IB finally comes out.

I have chosen the Intel Core i5 2500k as the CPU. I can't afford an i7 right now. And I am planning on two EVGA GeForce GTX 560 Ti FTW PCI Express 2.0 x16 Cards.]

The issue I am having is finding a new 1155 Mobo that supports 2 PCI-E 2.0 x16 at Dual x16. The Mobo I want is the new ASUS Sabertooth Z77. But it seems that it only supports x16/x8 for Dual SLI.

Why are new Mobo's even being released that don't support Dual x16 for SLI? Isn't this better for someone building an SLI system? The Sabertooth Z77 doesn't seem to support what you would expect to see in a High End Mobo.

Even the Maximus IV Extreme-Z Z68 doesn't seem to support Dual x16. [4 x PCIe 2.0 x16 (x16 or dual x8 or x8, x16, x16)]

The only board I have found so far that does support it is the Asus P8Z77 WS. [4 x PCIe 3.0/2.0 x16 (x16; x16/x16; x16/x8/x16 and x16/x8/x8/x8)] I will buy this if I have to but it has none of the features that make the Sabertooth and ROG boards better for gamers.

I play BF3, BF BC2, AA3, COD, CSS and a few others. Mostly BF3. I want a system that will not just run these but run them all well. I know allot of people will say that the CPU is too slow but i can't afford to spend $400+ on an i7. So the i5 2500k is the one I am getting.

So which board do I go with? How much of a performance loss, if any, will I have running that Mobo with the Dual SLI running at x16/x8? Would the P8Z77 WS be better? If so how?
6 answers Last reply Best Answer
More about dual nvidia please
  1. Best answer
    On ANY GPU in existence x8/x8 vs x16/x16 doesn't concern me. Even the forthcoming GTX690 an x8 isn't going to be saturated as PCIe 2.0 and laughable as PCIe 3.0. A PCIe 3.0 x8 = PCIe 2.0 x16; same bandwidth.

    The Ivy Bridge CPUs have been delayed until June/July and close to ditto with an Z77 MOBOs i.e. ASUS P8Z77 WS. Currently, the ASUS P8P67 WS offers the NF200 for x16/x16.

    A GTX 560 can't hardly fully saturate PCIe x4 (version 2.0). Nice article ->

    Getting either a P67/Z68 with x16/x16 requires an NF200 chipset -- any of these chipset have pros and cons; Pro = x16/x16 or up to 3-WAY SLI or 4-WAY CF; Con = adds some latency and you're still 'funneling' 32 lanes -> into 16 lane limit of the CPU.

    Another nice article ->,2910.html

    I would recommend either the ASUS P8Z68-V PRO/GEN3 or P8Z68-V/GEN3 -


    IF you haven't purchased anything yet then you might want to consider SB-E/LGA 2011 which offers 32 lanes (x16/x16) of PCIe 3.0 (CPU and MOBO) and the newer HD 7000 series is PCIe 3.0 and the GTX 600 series is PCIe 3.0 and are coming out anytime now.

    MOBO -
    CPU -

    The i7-3820 can OC to 4.75GHz (125MHz Strap x38 CPU Ratio)
  2. x8/x8 vs. x16/x16 is a non issue, even with today's top cards. You are looking at a couple of fps differences with GTX580 class cards, less with slower cards.
    Some vendors have added extra chips, at extra cost to provide additional lanes for those who want triple and quad sli.
    pcie 2.0 or 3.0 is not an issue either. Today's cards just don't push those limits.

    Regardless, if you are gaming on a single monitor, the 7970 or upcoming GTX680 will run anything very well.
    A single card will let you pick a less expensive motherboard, and avoid any possible microstuttering sli issues.

    The 2500K is as good as it gets for gaming today. The I7-2600K does not get you any important benefit for gaming which does not use more than two or three cores.
    the 2500K will OC just about as high. The extra $100 is just not worth it. You chose well.

    If you are looking at Z77 motherboards, then you should also be looking at ivy bridge which will show up at about the same time.
    Look for the 3570K which will be priced comparable to the 2500k, start at a higher clock, run 10% faster, clock for clock. The 22nm part should run cooler and OC higher.
  3. Right now it's a tough call as follows:

    $320 i7-3820 -
    $320 ASUS P9X79 PRO -

    $325 I7-2600K -
    $260 ASUS Maximus IV Extreme -

    /$210 ASUS P8Z68-V PRO/GEN3 -

    Only +$95 for LGA 2011 with it's expansion possibilities...
  4. Ok, so basically it really doesn't matter what the slots run at. The two GTX 560 Ti FTW's I am getting, or even two EVGA GTX 590 Classifieds, wouldn't take any performance hits if run at x16/x8 or even x8/x8.

    That's interesting. And here I thought I was getting jipped by the newer mobo's when actually they are giving you more bandwidth than is currently usable with any card on the market today and possibly even future cards.

    So I think I will go with the ASUS P8Z68-V PRO/GEN3. It has the best features out of other similar boards from other Manufacturers. And the price is good.

    And if the Sabertooth Z77 comes out by the time I have the money saved up then I will just get it. I like it the best because of the design and the added features it offers. Just have to see what it costs and when it get's released.

    Thank you very much for your help! :D

    EDIT: And yes I do plan to upgrade to an Ivy Bridge CPU. That's why I went with the 1155. I am also toying with the 2011 socket possibilities but I plan to buy before Ivy Bridge comes out so the extra money I would need to spend on the 2011 socket would stall my build. lol That and since the bandwidth issues are a non-concern I will just stick with 1155 cause it has everything I need.

    Again thank you everyone for your help! :D
  5. Best answer selected by etrnlxdarkness.
  6. This topic has been closed by Nikorr
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