M.2 Adapter. PCIE vs Sata type

RAGNES7 · August 9, 2022

In the end both will transfer data through a Sata Cable I belive. But one is gonna look like an Opened up Hard disk. Draws power same way as SSD do.

While the other option is drawing power through PCIE slot.

If anyone has used either of these, can you please suggest what is better

An0maly_76 · August 9, 2022

Clarification, what exactly are you trying to do? If you're going through a SATA or USB port, either will cut the speed to 500-550mbps or less. PCIe3 and PCIe4 are much faster, but require a dedicated slot in the motherboard, and I'm not aware of any adapters to use a PCIe3 or PCIe4 through SATA. I have something similar to the opened-up hard drive (SATA M.2 to SATA) looking adapter (limited to SATA's 500-550 mbps), as well as a portable M.2 adapter enclosure that connects via USB, but I'm pretty sure it runs at standard USB 3.0 speeds, not the full PCIe3 or PCIe4.

By contrast, PCIe3 / PCIe4 in dedicated M.2 slots average 2200-3400 mbps or more with PCIe3, and for boot drives, this is the best configuration. There are also PCIe slot cards and brackets for this as well for PCIe3 / PCIe4, but will likely be limited to PCIe3. Just keep in mind, as I found with my Sandy Bridge LGA1155, some older CPUs do not support booting from PCIe. I think this capability came about with Coffee Lake and AM4, I've heard ASRock now has an AM3+ board with an M.2 slot that appears to be PCIe3.

Some PCIe4s can hit 4000-5000 or more, but they run hotter and performance increase beyond 3400 is negligible. But I'm pretty sure running a PCIe version through anything but a dedicated motherboard M.2 slot, will not achieve full speed. Also, some slots supposedly can do PCIe OR SATA, and with motherboards that have multiple M.2 slots, sometimes one (or both) will disable certain SATA ports when occupied.

There are also what have been dubbed DIMM.2 adapters, which are what they sound like, an M.2 adapter that uses a DIMM slot. These appear decidedly SATA, from the power and data connections up top. The opened-up hard drive adapter you refer to is likely SATA only as well.

In summary, the opened-up hard drive-type you speak of are great for when a drive bay is available you don't otherwise need. The other similar type I have and the DIMM.2 come in handy when you have no free drive bay in a cramped SFF case and need an option that can be tucked away somewhere.

Here are some examples. Left to right, DIMM.2, SATA M.2 adapter, differences in M.2 key between SATA / PCIe, and the portable enclosure I spoke of...

Edited August 9, 2022 by An0maly_76
Revised, more info

Fl0yd- · August 9, 2022

1 hour ago, An0maly_76 said:

Clarification, what exactly are you trying to do? If you're going through a SATA or USB port, either will cut the speed to 500-550mbps or less. PCIe3 and PCIe4 are much faster, but require a dedicated slot in the motherboard, and I'm not aware of any adapters to use a PCIe3 or PCIe4 through SATA. I have something similar to the opened-up hard drive (SATA M.2 to SATA) looking adapter (limited to SATA's 500-550 mbps), as well as a portable M.2 adapter enclosure that connects via USB, but I'm pretty sure it runs at standard USB 3.0 speeds, not the full PCIe3 or PCIe4.

By contrast, PCIe3 / PCIe4 in dedicated M.2 slots average 2200-3400 mbps or more with PCIe3, and for boot drives, this is the best configuration. There are also PCIe slot cards and brackets for this as well for PCIe3 / PCIe4, but will likely be limited to PCIe3.

Some PCIe4s can hit 4000-5000 or more, but they run hotter and performance increase beyond 3400 is negligible. But I'm pretty sure running a PCIe version through anything but a dedicated motherboard M.2 slot, will not achieve full speed. Also, some slots supposedly can do PCIe OR SATA, and with motherboards that have multiple M.2 slots, sometimes one (or both) will disable certain SATA ports when occupied.

There are also what have been dubbed DIMM.2 adapters, which are what they sound like, an M.2 adapter that uses a DIMM slot. These appear decidedly SATA, from the power and data connections up top. The opened-up hard drive adapter you refer to is likely SATA only as well.

In summary, the opened-up hard drive-type you speak of are great for when a drive bay is available you don't otherwise need. The other similar type I have and the DIMM.2 come in handy when you have no free drive bay in a cramped SFF case and need an option that can be tucked away somewhere. Just keep in mind, as I found with my Sandy Bridge LGA1155, some CPUs do not support booting from PCIe, but I think this capability came about with Coffee Lake and AM4, I've heard ASRock now has an AM3+ board with an M.2 slot that appears to be PCIe3.

Here are some examples. Left to right, DIMM.2, SATA M.2 adapter, differences in M.2 key between SATA / PCIe, and the portable enclosure I spoke of...

exactly what I was thinking, +1.

mariushm · August 9, 2022

pci-e 2.0 : 500 MB/s per lane

pci-e 3.0 : 985 MB/s per lane

pci-e 4.0 : 1970 MB/s per lane

An M.2 connector can have 1, 2 or 4 pci-e lanes in it. So depending on pci-e version and number of lanes, you could have maximum speed anything between 500 MB/s and 7880 MB/s

The maximum effective speed will depend on the controller used on the SSD and also on memory chips used (MLC is faster than TLC which is much faster than QLC, and even between same type there's differences ex a 96 layer TLC chip may be faster than 112 layer chip, but the 112 layer TLC chip is cheaper so it's more used)

For example, B450 chipset on socket AM4 only creates pci-e 2.0 lanes, while the pci-e lanes coming from CPU are pci-e 3.0. The M.2 connector close to the CPU will have 4 pci-e 3.0 lanes (and therefore up to around 4 GB/s speeds if the controller on SSD can also achieve that) but the second M.2 connector will usually receive 2 or 4 pci-e 2.0 lanes from the chipset, so the maximum speed would be 1 GB/s or 2 GB/s

There are adapters that can be plugged in a pci-e slot and support 1 or 2 M.2 drives - usually the adapter simply routes 4 pci-e lanes from the slot, to the first M.2 connector on the adapter - that's the only NVME SSD supported. If the slot is pci-e 2.0, then you get up to 4 pci-e 2.0 lanes and maximum 2 GB/s.

The second M.2 slot is just SATA, and there's no connection to motherboard besides power - the adapter just offers a slot to plug the adapter in, and a SATA data connector to attach a SATA cable between the adapter and the sata port on your motherboard.