Rampage V Edition 10 - PCIe lane fail...

Sprayingmango

Sprayingmango

[H]ard|Gawd
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So there is a pretty big issue with the PCIe lane distribution on the Rampage V Edition 10 that I feel more users should be made aware of. If you are like me and run an M.2 drive, SLI vidya cards, and a PCIe SSD....you will not get full speed. It will either not allow the PC to boot, or you'll be stuck in an endless boot cycle....or you'll get X16 on one card, X8 on another, and your M.2 SSDs will not run full speed.

This is a pretty big deal considering ALL of these things worked flawlessly at full speed on the older Rampage V Extreme....so what's the deal?

I am running a 5960X with 40 PCIe lanes.

SLI 1080s in the exact slots Asus says to run them. I am running an M.2 950 Pro in the on-board M.2 slot. That is currently NOT even running at max link speed as reported by Samsung Magician...I still don't know why that is....

Anyway, at first my SLI was broken when I had the SLI config setup and the PCIe SSD in either the middle slot or the bottom slot...so I removed it and now SLI is working at max speed again.

Go here to see what the issue is: http://www.overclock.net/t/1613430/official-rampage-v-edition-10-owners-thread/150
 
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This is what magician reports now... so my 950 Pro is not running at full speed.... what the hell is going on?

ah5i8jW.png
 
Looks like M.2 is wired through chipset that is PCI-E 2.0 x4.

And yes, that bullshit wiring is bullshit indeed.
 
Sprayingmango said:
So there is a pretty big issue with the PCIe lane distribution on the Rampage V Edition 10 that I feel more users should be made aware of. If you are like me and run an M.2 drive, SLI vidya cards, and a PCIe SSD....you will not get full speed. It will either not allow the PC to boot, or you'll be stuck in an endless boot cycle....or you'll get X16 on one card, X8 on another, and your M.2 SSDs will not run full speed.

This is a pretty big deal considering ALL of these things worked flawlessly at full speed on the older Rampage V Extreme....so what's the deal?

I am running a 5960X with 40 PCIe lanes.

SLI 1080s in the exact slots Asus says to run them. I am running an M.2 950 Pro in the on-board M.2 slot. That is currently NOT even running at max link speed as reported by Samsung Magician...I still don't know why that is....

Anyway, at first my SLI was broken when I had the SLI config setup and the PCIe SSD in either the middle slot or the bottom slot...so I removed it and now SLI is working at max speed again.

Go here to see what the issue is: http://www.overclock.net/t/1613430/official-rampage-v-edition-10-owners-thread/150
Click to expand...

First off, you do not need to make a separate thread for this. One thread concerning your problem is sufficient.

lolfail9001 said:
Looks like M.2 is wired through chipset that is PCI-E 2.0 x4.

And yes, that bullshit wiring is bullshit indeed.
Click to expand...

Not according to the wiring diagram I've seen for the RVE10. According to the wiring diagram I'm looking at right now (from TweakTown) the M.2 port comes from the CPU's lanes. If I'm reading this right the M.2 slot can be fed from a variety of sources. Depending on how the system is setup, you could lose bandwidth to the x16 slots or to the M.2 slot. Unfortunately, I never tested this motherboard with SLI specifically. My M.2 / U.2 test went fine.

As I said in the other thread on this topic, the Rampage V Edition 10 doesn't have a PLX chip. Therefore it isn't going to be as flexible with its lane configuration as some motherboards are that do have them. The lane allocation on the Rampage V Extreme is different and doesn't seem to suffer from this problem. It also doesn't have as many integrated devices as the newer motherboard does. In hindsight, I think ASUS should have put a PLX chip on the motherboard and made sure that the M.2 slot always ran at full speed no matter what.
 
Dan_D said:
According to the wiring diagram I'm looking at right now (from TweakTown) the M.2 port comes from the CPU's lanes. If I'm reading this right the M.2 slot can be fed from a variety of sources. Depending on how the system is setup, you could lose bandwidth to the x16 slots or to the M.2 slot. Unfortunately, I never tested this motherboard with SLI specifically. My M.2 / U.2 test went fine.

As I said in the other thread on this topic, the Rampage V Edition 10 doesn't have a PLX chip. Therefore it isn't going to be as flexible with its lane configuration as some motherboards are that do have them. The lane allocation on the Rampage V Extreme is different and doesn't seem to suffer from this problem. It also doesn't have as many integrated devices as the newer motherboard does. In hindsight, I think ASUS should have put a PLX chip on the motherboard and made sure that the M.2 slot always ran at full speed no matter what.
Click to expand...


THANK YOU for this explanation Dan! This makes sense. I wonder if I disable the onboard Wifi / Bluetooth / 3.1 controller if that will free up lanes for the M.2? Or will it always be gimped?

I'm sad that it wont run at full speed, I was planning on getting a 960 Pro but that will be pointless now.

I also wonder if I got an Asus Hyperkit and ran it on the U.2 connector if it will go full speed? Or does that not make a difference....?
 
Sprayingmango said:
THANK YOU for this explanation Dan! This makes sense. I wonder if I disable the onboard Wifi / Bluetooth / 3.1 controller if that will free up lanes for the M.2? Or will it always be gimped?

I'm sad that it wont run at full speed, I was planning on getting a 960 Pro but that will be pointless now.

I also wonder if I got an Asus Hyperkit and ran it on the U.2 connector if it will go full speed? Or does that not make a difference....?
Click to expand...

I don't know if disabling the WiFi or Bluetooth controller will help or not. However, its easy to find out. Secondly, the Hyperkit may work but it will reduce your link speed for the GPUs. Also, the fourth PCIe x16 slot shares bandwidth with the U.2/M.2 ports. Keep that in mind.
 
So I solved this issue today! I swapped out my CPU - 5960X for a 6850K Broadwell-E. This helped me discover what the issue was.

The Broadwell-E chip runs at 3.6 GHz and when I set my XMP profile for my Corsair Dominator Platinum 2800 ram, it sets a 100MHz BCLK. Previously, on my Haswell-E 5960X it set a 125MHz BCLK.

For reasons I don't fully understand, this caused the PCI-e lanes to not communicate properly, thus causing me to NOT achieve full speed on my M.2 SSD's!

I'm now back at full speed and everything is fine. Maybe someone can explain why this happened?? Hopefully this can help other RVE10 owners if they discover the same issue.

G6VG61s.png


T17aHvQ.png
 
buhbuhfet said:
looks like buggy bios, nothing new with asus
Click to expand...

True, but it isn't as if the other major players in the industry are any better than ASUS in this regard.

Nathan_P said:
PCIe is known to be unreliable once you take the clock above the reference of 100Mhz
Click to expand...

Yes, but X99 supports various strap settings (100MHz, 125MHz, 150MHz, and 167MHz) and thus the PCIe bus would be using a divider and not running at speeds in excess of 100MHz. That said, sometimes the actual settings vary somewhat from the spec setting. An ASUS motherboard might actually run the base clock at 99.7MHz or something like that while MSI tends to run closer to 99.0MHz or something like that. At 125MHz, the actual clock rate for the PCIe bus could have been slightly over 100MHz. That certainly could have caused an issue in this case.
 
Thanks Dan,

Another problem with this board has popped up....the USB 3.0 ports on the back seem to cause certain devices to stop responding. My Logitech keyboard (G910 orion spark) will randomly stop responding no matter which port it's in. My G900 mouse and G933 headset seem to work fine. Running the latest Logitech Gaming Software and all devices have the latest firmware. Others on the Asus ROG forum report the same weird USB issues.
 
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