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Thread: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?




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    Default Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    Please correct me if I am wrong:

    1.
    I installed both of my 290x.
    1 into PCI E Slot 1
    1 into PCI E Slot 4
    They should run each with 16 PCI E 3.0 Lanes. (Page 19 in the Manual)

    2.
    The MB has the ability to install 2 m2 SSD.

    3.
    They can be run from the CPU with PCI EXPRESS Lanes.
    or
    By the chipset of Z97.


    I want to buy the
    Samsung SSD XP941 512 GB
    and it should be as fast as possible.

    How many lanes will be left, keeping in mind that 32 are in use?
    Intel specs are 1x 16 and 1x8 Lanes. How can it be Z97 Extreme9 offers 2 x 16?


    Should I use m2_1 or m2_2?
    M2_1 supports up to gene 3, 4x. Does this mean 4 Lanes? Do I still have 4 Lanes left?

    How many Lanes does the board have, overall?

    What happens if I install a pci-e ssd like Mushkin Scorpion with 4 pci-e lanes?


    Any help is welcome.


    Regards from Germany
    Last edited by Wotan16; 08-13-2014 at 09:11 AM.

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    SandsOfTime is offline Member
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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    your system has 16 PCIe 3.0 lanes from the cpu and 8 PCIe 2.0 lanes from the chip set. These lanes are switched with PLX chips (4 of them between slot PCIE1 and PCIE2, another 4 between PCIE3 and PCIE4) between the PCIe slots and the ssd slots. This is possible because no PCIe device, graphics card or ssd, occupies the lanes with data transfer all the time.

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    SandsOfTime is right about the PCIe 3.0 lanes in the CPU, and the PLX chips. The CPU has 16 PCIe 3.0 lanes. The Z97 chipset has eight PCIe 2.0 lanes.

    The M2_1 slot uses PCIe 3.0 lanes from the CPU, and x4 means it is connected to four PCIe 3.0 lanes.

    The M2_2 slot uses PCIe 2.0 lanes from the Z97 chipset, and is an x2 connection, two PCIe 2.0 lanes.

    A Samsung XP 941 must be used with an x4 connection (M2_1) to use its full speed potential. Internally the XP941 runs at PCIe 2.0 speeds, but it will work in the M2_1 slot, which is the only x4 M.2 connection on the board.

    A PCIe x4 SSD used in this board should be used in one of the PCIe 3.0 slots (PCIE1/PCIE2/PCIE4/PCIE5), since the one PCIe 2.0 slot (PCIE3) is only an x2 slot electrically.

    How well the PLX chips work with one or more video cards, and SSDs in the M.2 slots, or a PCIe SSD, remains to be seen. What connections are reported for your two 290's with GPU-Z, etc?

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    GPU-Z 0.7.9 shows each 290x running in PCI-E 3.0 with 16 Lanes.

    I couldnt get many tech info about the board. So i checked the
    downloadable manual before I bought it.
    Now it looks I might have done wrong.

    Any way to check the transfer speed in real?
    I dont wanna sell all and wait for 2011-3 ..

    Any advise whats faster?
    1. 2 or 3 ssd in raid connected by sata
    2. M2 ssd connected with 4 pci-e3 m2_1 ? Or maybe less? Lanes?
    3. Same with pci-e 3
    4. M2 ssd connected to the m2_2? Only 2.0 (1000mb/sec)



    This is all very confusing for me....


    Thanks a lot.
    Last edited by Wotan16; 08-14-2014 at 07:06 PM.

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    Confused now? It's about to get worse...

    Not all M.2 SSDs are strictly PCIe drives, most of them are really identical to standard SATA III SSDs in terms of speed.

    Exceptions to this are the Samsung XP941 and the Plextor M6e, that are truly PCIe SSDs that are not controlled by the board's SATA chipset. All the other M.2 SSDs are really standard SATA SSDs that use the board's SATA controller.

    Given true PCIe SSDs like the Samsung XP941 and Plextor M6e, the number of PCIe lanes they can use is determined by the SSD itself. They each only have so many PCIe lane connections built into them, and cannot use more than that.

    The Plextor M6e can only connect to two PCIe lanes, even if connected to the Ultra M.2 slot that uses four PCIe lanes.

    The Samsung XP941 is the only four PCIe lane SSD available at the time of this post. I'm not sure if it will work if connected to a two lane M.2 port, but if it does then its speed would be limited by only using two PCIe lanes instead of four.

    Both of these SSDs can operate internally only at PCIe 2.0 speeds or less, their controllers are not capable of PCIe 3.0 speeds. You would gain very little to nothing using them on a PCIe 3.0 connections (I've tested that on the M6e.) But you would put an XP941 on the Ultra M.2 port since it is a four lane (x4) connection.

    Two high end standard SATA III SSDs in RAID 0 would be faster in sequential read and write speeds than a Plextor m6e, ~1000MB/s vs ~750MB/s read/~500MB/s write for the M6e.

    The XP941 would be about equal to three high end SATA III SSDs in RAID 0.

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    Thumbs up Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    Thank you for the advise.
    I ordered the xp941 512GB.
    Hoping it will run full speed with my crossfire system.

    Regards from Germany

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    The information here is not incorrect but a little confusing, so I try to give you a wider scope.

    Technically it is correct that:
    16 lanes PCIe 3.0 are available through CPU
    8 lanes PCIe 2.0 provided through the chipset.

    It is also true that:
    M.2#1 uses 4 lanes of PCIe 3.0 from the CPU (up to 32 Gigabit/s [128b130b] or ~3,94 Gigabyte/s)
    M.2#2 uses 2 lanes of PCIe 2.0 from the chipset (up to 10 Gigabit/s [8b10b] or 1 Gigabyte/s)

    By math this means if you use both M.2 Slots you still have left:
    12 lanes PCIe 3.0 from the CPU (bandwith ~11,82 Gigabyte/s) to/from your graphics system-bus.
    6 lanes PCIe 2.0 from the chipset (bandwith 3 Gigabyte/s) to/from your sata-bus.

    But thats only half of the truth.

    ASRock build this Board with an 48-Lane PLX-PXE 8747 gen 3 switch chip. This device is linked to the CPU 16 Gen 3 lanes entirely and all PCIe 16x-Slots (except #3) hooked up to the switch, same as the M.2#1 i guess, please correct me when im wrong.
    So 48-lane full-duplux means this switch can send AND receive: ~47,26 Gigabyte/s simultaneously.

    While using Crossfire or SLI or dedicated PhysX lots of the memory traffic between the card can bypass the CPU and can be streamed directly between cards (copy from primary-SLI-card).

    This board offers following PCIe-Gen-3-GPU setups by spec:

    16x/0x/16x/0x
    8x/8x/16x/0x
    8x/8x/8x/8x

    While some other Z97 boards not even offer SLI 8x/4x + 4x for dedicated physx work properly, this is a total blast and enables all kinds of configurations that one would call "surplus".

    Also consider that PCIe delivers rates at full-duplex-mode, so the CPU can send AND receive simultaneously at ~15,75 Gigabyte/s to the PLX-PXE, which actually is sufficient for pretty any card-combination.
    So correct would be from 48 lanes Gen3 (~47,26 Gigabyte/s full-duplex) of the PLX-PXE-chip the CPU is linked with all of it's 16 lanes Gen3 (~15,75 Gigabyte/s full-duplex).

    Remember that maintaining RAM-transfers @ ~31Gb/s is considered out of spec by intel and of cause that you need fast enough RAM to satisfy such bus-transfers IF they ever shoudl occur ...haha. like installing a game from a 840pro raid onto your xp941 while simultaneously playing metro last light with triple SLI + dedicated phys ...lol. WHo got the money to find out? Im close, but triple-SLI is too much for me :D Well to be honest I think even quad-sli plus xp941 would be absolutely no problem... thats what this board solely is designed for if you see it serious.

    To give a clear answer... technically with your 2x 290X - each linked 16x Gen3 to PLX-PXE which itself linked 16x Gen 3 to CPU... your M.2 still will be linked 4x Gen 3 to the PLX-PXE which still itself is linked 16x.

    Just some little magic. :D

    Now one might think to better use M.2#2 in part with SLI/Crossfire since it onlky take PCIe lanes from the chipset but not the CPU but that is not true too, because IF your game uses caching objects on demand from drive, then THIS is definetly a bottleneck and CAN produce stutter (remember Might and Magic Legacy) so you want that transfers to be as fast as possible no matter it may "slow" down your SLI/Crossfire link to ~11,82 Gigabyte/s (12x lanes) "only"...until that moment is over, thats the benefit of a SWITCH!

    PS: Even with enthusiast multi-GPU Gen 2 8x or Gen 3 4x (@ ~4 Gigabyte/s) is not bottlenecking, the loss is considered minor (<5%) compared to Gen 3 16x, so the GPU-cards and the m.2s that actually bottleneck on this board may be put the market in future ... maybe next year :D :D
    Last edited by Incriminated; 08-22-2014 at 06:01 AM.

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    I forgot to say that the PLX-PXE is able to multi-cast.

    So when CPU wann transfer game-files into VRAM of a Quad-SLI... it addresses the transfers as multicast and sends it to the PLX-PXE at ~7.88 Gigabyte/s while the PLX-PXE does multicast that ~7,88 Gigabyte/s transfer on-the-fly up to four devices (Quad-SLI 8x each) at each ~7,88 Gigabyte/s.

    That way the PLX-PXE is maintaining a total bandwith of ~31,5 Gigabyte/s (output) plus ~7,88 Gigabyte/s (input) while only using 8x Gen3 Lanes of the CPU, and the CPU haveing 8x Lanes left unused... in Quad-SLI!!!.

    PLX-PXE chips are great... same brand-chips are in the 690 nvidia reference design.

    Also the fastest M.2 out there is the Samsung we are talking about... and while it is linked to PLX-PXE using 4-lanes of that... the transfer-rates of that cool thingy peak 1170 Megabyte/s by spec. So in practice to handle the particular transfers of the fastest M.2 in the world, the PLX-PXE would only occupie max 2 lanes Gen3 PCIe to the CPU (delivering up to 1969 MB/s send and receive).

    So the best answer to reply to this topic would be: ENOUGH, because only way to get theoretically short on Gen 3 lanes is using Dual-SLI (16x/16x) + an M.2-Ultra (max. 2 gen3 lanes from the CPU)... then trying to add a dedicated PhysX what way tear it down to 16,8,8 or even 8,8,8 but in Dual-SLI there is practically not enough GPU-power to limit even on 8,8 Gen3...., still not with a dedicated PhysX.

    Maybe a Triple SLI + dedicated PhysX + M.2-Ultra of the next generation will run into very little limitations IF, i repeat, IF you transfer hell of data from a SSD-Raid to the M.2-Ultra WHILE gaming same time...lol

    So i repeat: Enough!
    Last edited by Incriminated; 08-22-2014 at 11:20 PM.

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    Exclamation Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    Thank you Incriminated very much for this awesome explanation.
    This should become a sticky for the Z97 Extreme 9 Forum.
    I will link it to a german forum too.

    Today my Samsung XP941 arrived. But it is midnight now and i need to sleep.
    Hopeing to install it tomorrow.
    Any advise what programs to use for testing, so others benefit from it also?

    Again, thanks a ton
    Last edited by Wotan16; 08-23-2014 at 06:02 AM.

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    Default Re: Asrock z97 extreme 9 with 2 290x - How many lanes left for a m2 SSD?

    Quote Originally Posted by Wotan16 View Post
    Thank you Incriminated very much for this awesome explanation.
    This should become a sticky for the Z97 Extreme 9 Forum.
    I will link it to a german forum too.

    Today my Samsung XP941 arrived. But it is midnight now and i need to sleep.
    Hopeing to install it tomorrow.
    Any advise what programs to use for testing, so others benefit from it also?

    Again, thanks a ton

    Well i was a little wrong about the M.2 Ultra Slot beeing linked to the PXE, so i correct myself upon that. Thanks to someone posting the diagram from Asrock support on anandtech we know it is directly linked to the CPU. So if it really consumes 4 lanes Gen3 (the XP941 needs only 4 lanes Gen2) theres still 12x lanes Gen 3 left.

    Now on Dual-SLI 12x is available, because cards are at 16,16... although they dont even need 8x to operate at 99.9% performance, so practically they dont take advantage of 12x. And on Triple or Quad-SLI the switches uplink is limited to 8x due to the slowest card beeing 8x. So Triple or Quad of actual top high end cards on the other hand could take advantage to gain another 1% of 12x uplink, but they are limited electrical 8x. :D :D :D So even 12x or 8x doesnt matter in any case.


    I also posted in that thread on anandtech a detailed explaination why even 8x Gen3 in triple SLI is enough for 3D-Surround triple display WQHD (1440p) @ 144hz or fps in terms of bandwith.

    See here:
    ASRock Z97 Extreme9 Ultra M.2 x4 and PCIe lanes - Page 3 - AnandTech Forums

    12x Gen 3 equals ~11,8 Gigabyte/s available bandwith or mathematically 24x Gen2... thats enough to push GPU-VRAM transfers from the RAM to the PLX-PXE which multi-casts it to all cards without using additional CPU-cycles. In triple-SLI without dedicated fourth PhysX card this board also delivers 16x Gen3 on the primary GPU (16,8,8). So that means the VRAM uplink transfers peak at the max 8x Gen3 speed (~7,9 Gigabyte/s) to the PXE, the PXE then simultaneously multi-casting it to 3 cards which receiving on the 8 lanes. Now the two non-primary cards still have the capability to SEND their frames (full-duplex) on at least 4 lanes to the the primary while the primary still have the capability to receive that traffic on 8 unused lanes (of it's 16 @ the PXE).

    And that means while your CPU loads data from RAM to the PXE and that one is multicasting it to 3 cards overall at max bandwith on each of the 4 ports (~7,9 Gigabyte/s each, total ~31,6 Gigabyte/s) during "loading-times", in that moment each of the non-primary cards have still enough bandwith left to SEND (duplex) about 280 frames @ 1440p/32bit to the primary card simultanesously, which can still receive (8x of 16x free to receive) about 560 frames of that simultaneously, without any problems. In that moment the PXE would process a total bandwith of magestic ~47,35 Gigabyte per second overall send and receive on all ports incl. uplink. During that it needs only 8 lanes Gen3 from the CPU overall to achieve that when having a PXE-switch chip equipped. Thats ridicolous but true!

    No bottleneck! And 4K only goes 60hz... so still no bottleneck here... that math is on anandtech forum, if you really want to know (see link above).

    All that while still using a M.2 Ultra that fully takes advantage of 4 lanes Gen3 from the CPU.

    Although when adding dedicated PhysX to the Triple-SLI it shortens your primary-SLI card from 16x gen3 to 8x gen3, still having the same non-effective 12x uplink (effective 8x).... but overall that 8x for all 4 cards including primary (no more 16) is still enough for any triple-SLI combination with any dedicated physx-demands... because the framebuffer-transfer-work occuring is the most demanding... and is what puts up the limits when you go multi-display and high resolutions in terms of bandwith. So now the Triple-SLI beeing at 8,8,8 + dedicated PhysX using 8 still not bottlenecking because the math says we can deliver 144 frames @1440p and 32 bit to 3 displays EACH (~2 Gigabyte/s send on two cards each and receive ~4 Gigabyte/s on primary card). During that workload cosnuming 4 lanes gen3 on primary and 2 each on the second and third, the primary card card still have 4 lanes left The vram-caching that invokes CPU-bound RAM-transfers to the VRAM usually take place at high bandwith during loading-times of a game and only minor object- or texture-caching during the game does occur in the middle of the game, depending on engine-capability and ability to take advantake of high available amount of VRAM. So now IF it still may occur during the middle of the game... while pumping 1440p @144hz we still have 4x Gen3 or another ~4GB/s bandwith left unused for the CPU available to adress VRAM-transfers through multicast PXE simultaneously without a single frame drop in fps of our 144 on 3 displays.

    The problem is processing power... not bandwith!

    I dont know what you mean things to test... run 4k-3D-Surround-Setups... then try running ASSSD or anything like that, CrystalDiskMark or Anvil while benchmarking and compare it to the results without stressing the M.2 if you really interested. But i guess there will be no difference at all .... or 1%... because PXE-uplink of 8x Gen3 is enough for even Quad-SLI beeing only 1% slower than 16x Gen3 PLX-uplink (X79 with PXE). :D

    So you decide yourself if you want pay double the price for mayinboard and triple the price for the CPU only to get up to 1% more multi-GPU performance... while the single-thread performance of a 4790K is higher than any Haswell-E to be expected :D

    PS: Also there is chance to unlock at least 14x upink to the PXE while the M.2-Ultra is unused using WIndows Power Schedule to save power on PCIe... possibly... so you should bench if that makes a difference too ;p

    Feel free to copy any of what i said to anywhere you want, but take this hint: All info came without any warrant. I might dont knoiw every thing and every aspect. :D

    And BTW whatever you do, when you go Triple-Display @ "only" 1440p usually even the CPU 4790K will limit at some point on the way up to 144hz in most games... because such wide-range view of a virtualworld usually triples the amount of objects and triples the amount of draw-distance-surface which are factors that run into limitations regarding the main-game-CPU-thread... the 2011 socket CPUs sadly dont help on that problem. :(

    Just try Rift and visit some crowded place - gives you 30-40fps with 4790K at max fx, details and distances :D Unplayable on a 2011 i guess...

    Only light at the end of the tunnel here is the arrival of DX12, what deals with CPU-bottlenecks regarding draw-calls that usually tend to explode exponentially with wider FOV (multi-display), larger resolutions and high draw-distance, but thats a lot of time to wait for it to appear and it's still not clear if DX11-games will really benefit from DX12 cabable OS in general, while it seems to be clear that MS wont make it available on 7... to push 8 & 9. Since lack of alternative there is no choice then to hope with DX12 everthing will be better :D
    Last edited by Incriminated; 08-23-2014 at 11:50 AM.

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