Motherboard Asus H97I plus - is the M2 a PCI 3.0 4x

SpaceTofu

Caliper Novice
Original poster
Jun 18, 2019
21
11
Hi all

I'm a happy owner of a Asus H97I plus, currently sporting a Samsung SSD.
I wanted to step it up and get a nVMD. I was wondering if the M2 connector is the fastest out there ? I wouldn't want to bottleneck the nVMD.
I ideally would like to get my hands on a Samsung 970 Pro.

I thought such a forum of SFF enthusiasts would be the perfect place to ask about my H97 ( and I am actually thinking of perhaps changing to a thin ITX, depending to the answer I get on the above!)
 

SpaceTofu

Caliper Novice
Original poster
Jun 18, 2019
21
11
that board's m.2 slot is pcie 2.0 x2. it will bottleneck any nvme ssd.
Oh dear! It looks like I "need" a new ITX system!
May I ask you how you know that? Not even on their spec PDF is mentioned.
Actually the board has a PCIe 3.0 x16 slot so I would have hoped also the M2 was PCI 3 x16?
 

tinyitx

Shrink Ray Wielder
Jan 25, 2018
2,279
2,338
Oh dear! It looks like I "need" a new ITX system!
May I ask you how you know that? Not even on their spec PDF is mentioned.
Actually the board has a PCIe 3.0 x16 slot so I would have hoped also the M2 was PCI 3 x16?
Because the motherboard gets the lanes from the chipset H97, which supplies PCIe 2.0 lanes only.
(The PCIe 3.0 x16 slot gets its x16 lanes from the CPU.)
In those days, the M.2 slot is basically PCIe 2.0 x1 or x2.
 

SpaceTofu

Caliper Novice
Original poster
Jun 18, 2019
21
11
That's very informative, thank you miniitx.
Am I right in thinking then they if the nVMD drive with the OS would be plugged into the M2 port, it would constantly put the CPU under stress and I could see a decrease in performance in those rare times when I do CPU intensive operations?
Would then a M2 PCIE adapter be a good compromise for me ( the PCIE slot on my board is free) or would that come with its own drawbacks too?

Thank you
 

Valantar

Shrink Ray Wielder
Jan 20, 2018
2,201
2,225
That's very informative, thank you miniitx.
Am I right in thinking then they if the nVMD drive with the OS would be plugged into the M2 port, it would constantly put the CPU under stress and I could see a decrease in performance in those rare times when I do CPU intensive operations?
Would then a M2 PCIE adapter be a good compromise for me ( the PCIE slot on my board is free) or would that come with its own drawbacks too?

Thank you
An m.2 adapter in your x16 slot should provide full 3.0 x4 speeds. There shouldn't be any noticeable difference in CPU load, there's just a hard limit on the throughput of the drive. PCIe 2.0 x2 is a quarter the speed of 3.0 x4, which tops out at around 3.5GB/s, so the highest sequential speeds you'd see would be around 8-900MB/s. Fater than SATA, but not by much. As for random I/O, it might actually not be noticeably slower - as long as it supports the NVMe protocol, that is. Random I/O never really saturates the PCIe link, but is limited by the SSD controller.
 

SpaceTofu

Caliper Novice
Original poster
Jun 18, 2019
21
11
So in other words the M.2 adapter, providing the full 3.0 x4 speeds, is not going to bottleneck even the fastest Samsung 970 pro?
Sorry I'm not too tech-savvy!
 

Valantar

Shrink Ray Wielder
Jan 20, 2018
2,201
2,225
So in other words the M.2 adapter, providing the full 3.0 x4 speeds, is not going to bottleneck even the fastest Samsung 970 pro?
Sorry I'm not too tech-savvy!
It shouldn't, no. The PCIe in the x16 slot comes directly from the CPU, not the chipset, and is 3.0, so it should allow any 3.0 drive to run at full speed.
 
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