NVME bandwidth

[Vibes NoVibes]

Do all NVME slots on a MB come with the same bandwidth/speed? I have a Z390 Aorus Ultra and keen on using Adata XPG Gammix S70 2TB | PCIe Gen 4.0 NVMe Internal SSD - Buy Online (mdcomputers.in). It's GEN4 drive but compatible with GEN3 MBs.

[Action_Johnson]

Sorta. Depends on how many of your PCI-E lanes you're occupying, the rated speed of the slot, and the rated speed of the drive. 

 

I've seen PCI-E X2 NVMe slots before, usually they're X4. Using a PCI-E 4.0 drive in a 3.0 system just means you'll be running at PCI-E 3.0 speeds, so you'll have a theoretical max of about 3500MB/s. 

 

Now whether you get that or not is another story... both on the hardware and software end. If it's your C:\ drive, you'll never realize those speeds because of the I/O windows is constantly doing. On the hardware end, sometimes the chips get swapped mid-cycle, and the advertised speed isn't the actual speed...

 

Here's what my results are using a WD SN750 in a PCI-E 3.0 slot:

 

[suedseefrucht]

2 hours ago, Vibes NoVibes said:

Z390 Aorus Ultra

mb_manual_z390-aorus-ultra_1001_190219_e.pdf (gigabyte.com)

Your mainboard has 3 M.2 slots. Each with PCIe x4 (4 PCIe lanes) from the chipset.

Your mainboard uses PCIe 3.0, so 1 GB/s per PCIe lane.

But the communication between chipset and CPU (DMI) is PCIe x4.

So if all of your SSDs are used at once, they share 1 PCIe x4 lane to the CPU.

Network, Sound and other stuff from the chipset also runs through these 4 PCIe lanes.

 

PCIe lanes for your graphics card dont go through the chipset. They go directly to the CPU.

Modern CPUs have 20(24) PCIe lanes. 16 for the graphics card and 4 for an M.2 SSD (and 4 for DMI).

 

Your mainboard's manual says: If an SSD is placed in the M2M slot, SATA3 4 and SATA3 5 wont work.

Also if you place an SSD into the M2P slot, your PCIe x4 expansion slot will only be x2.