Asus X99-Deluxe/U3.1 + Samsung 950 Pro (250GB) M.2 Speed Issues?

Hello,

I have the following:

- Asus X99-Deluxe/U3.1
- Intel i7-5820K Extreme Hex Core CPU Processor (3.30GHz, 15MB Cache, 28 Lanes)
- Samsung 950 PRO NVMe M.2 256 GB Solid State Drive
- Asus STRIX GTX970-DC2OC-4GD5 NVIDIA GeForce GTX 970 Graphics Card

I have only the Asus Graphics Card in the PCIEX16_1 which is running at PCI-E 3.0 16x as expected. I have removed the USB3.1 card that comes with this motherboard for testing purposes so I literally only have the Graphics card installed.

The board has an onBoard M.2 x4 Rev 3 connector which the Samsung 950 PRO is installed into.

I believe this connector should allow 32Gb/sec bandwidth (since it uses PCI-E 3.0 x 4) - please note there is also an optional card where you can add the M.2 (or a second M.2) into a PCI Express slot - I'm NOT using this card, just the onBoard connector.

Samsung Magician says the following:
- Controller: Samsung NVMe Controller (Driver Ver: 1.4.17)
- PCIe Slot: PCI Express Root Port 1 - 2F03
> Link Speed Cur: 4Gbps, Max: 8Gbps
> Link Width Cur: x4, Max: x4
> Bandwidth Cur: 16Gbps, Max: 32Gbps

The performance data also suggests this - the read speed should be a lot higher but seems to be reduced, whereas write speed which is a lower number is over the actual "Upto Speed".

It appears as if my SSD is running at PCI-E 2.0 speeds? The bandwidth is being throttled. Any ideas how I make it go to 32Gbps instead of 16Gbps?

Thanks in advance!

 

Believe it or not, I've just stumbled across the solution.

I am using high FSB Corsair Dominator sticks and had them using an XMP (Extreme Memory Profile) - essentially my memory was overclocked.

I thought I'd try running in "normal" mode ie. stock settings and when I checked, the Samsung Magician is now showing as 32Gbps!!

The motherboard must sacrifice something to run the Memory at the higher clock speed which means it can't run the M.2 at PCI-E 3 and has to drop it to PCI-E 2.

Worth baring in mind for anyone else trying to achieve these elusive 32Gbps speeds