SSD M.2 slot vs PCIe adapter

[Venom_7]

I'm buying a M.2 PCI Express 3.0 x4 240 Gb chip for my ASUS Z97-A based PC. The Q is if it's better (faster data transfer or boot-up) to connect to the M.2 slot built-in the Mobo or to connect to the PCI-e interface through an adapter like this one

https://www.amazon.com/gp/product/B017YUCAXS/ref=ox_sc_sfl_title_4?ie=UTF8&psc=1&smid=A4UCFL9LU89NR

 

[Pinhedd]

They are logically identical; it does not matter.

EDIT: A side note,

M.2 slots multiplex SATA and PCIe. In order to facilitate this multiplexing, the M.2 connector is usually pinned to a SATA port on the chipset and PCIe lanes on the chipset.

Many motherboards pull their 1x and 4x PCIe slots from the chipset as well. In some cases, the same PCIe lanes are used for both and a firmware setting is used to toggle between them (using the M.2 for PCIe may disable a 1x or 4x slot).

However, Intel's CPUs also have their own PCIe root ports which are independent from the PCIe root ports on the Intel Platform Controller Hub. The PCIe lanes on the CPU have faster access to the system memory, but since Intel's CPUs do not have integrated SATA transceivers, it's not possible to pin them out as an M.2 port.

That adapter could in theory permit an NVMe SSD to access the system memory through the CPU's PCIe ports rather than the PCH's PCIe ports. However, the performance difference would be nigh undetectable.

 

[roy2115]

They are logically identical; it does not matter.

EDIT: A side note,

M.2 slots multiplex SATA and PCIe. In order to facilitate this multiplexing, the M.2 connector is usually pinned to a SATA port on the chipset and PCIe lanes on the chipset.

Many motherboards pull their 1x and 4x PCIe slots from the chipset as well. In some cases, the same PCIe lanes are used for both and a firmware setting is used to toggle between them (using the M.2 for PCIe may disable a 1x or 4x slot).

However, Intel's CPUs also have their own PCIe root ports which are independent from the PCIe root ports on the Intel Platform Controller Hub. The PCIe lanes on the CPU have faster access to the system memory, but since Intel's CPUs do not have integrated SATA transceivers, it's not possible to pin them out as an M.2 port.

That adapter could in theory permit an NVMe SSD to access the system memory through the CPU's PCIe ports rather than the PCH's PCIe ports. However, the performance difference would be nigh undetectable.

What about heat considerations? Would putting the SSD in a PCIe adapter keep it cooler than operating in the m.2 slot, which seems to be pretty cramped?

 

[cat1092]

They are logically identical; it does not matter.

EDIT: A side note,

M.2 slots multiplex SATA and PCIe. In order to facilitate this multiplexing, the M.2 connector is usually pinned to a SATA port on the chipset and PCIe lanes on the chipset.

Many motherboards pull their 1x and 4x PCIe slots from the chipset as well. In some cases, the same PCIe lanes are used for both and a firmware setting is used to toggle between them (using the M.2 for PCIe may disable a 1x or 4x slot).

However, Intel's CPUs also have their own PCIe root ports which are independent from the PCIe root ports on the Intel Platform Controller Hub. The PCIe lanes on the CPU have faster access to the system memory, but since Intel's CPUs do not have integrated SATA transceivers, it's not possible to pin them out as an M.2 port.

That adapter could in theory permit an NVMe SSD to access the system memory through the CPU's PCIe ports rather than the PCH's PCIe ports. However, the performance difference would be nigh undetectable.

What about heat considerations? Would putting the SSD in a PCIe adapter keep it cooler than operating in the m.2 slot, which seems to be pretty cramped?

Yes, the SSD (SATA-3 or NVMe) will run much cooler when plugged into a PCIe slot via adapter versus on a hot MB. Even if the devices reports normal temps, still the MB is hot, the last place one wants their expensive (examples, Samsung 950/960/970 PRO NVMe) SSD in under a GPU.

Amazon has a Sintech x4 adapter with replaceable small fan, speed can be adjusted with the installed knob, or if not needed, turned off with the same.

https://www.amazon.com/Sintech-M-Key-Samsung-SM951-PM951/dp/B01NAQPE6J/ref=sr_1_fkmr0_2?s=electronics&ie=UTF8&qid=1532458064&sr=1-2-fkmr0&keywords=sintech+PCIe+x4+adapter+with+fan+for+NVMe+SSD

I have two of these in usage, fortunately haven't needed the fan for my 512GB Samsung 950 PRO NVMe, however a lower cost PCIe x4 240GB MyDigitalSSD BPX with it's Phison E7 controller needs it. There's a killer deal on this NVMe SSD at the moment, much less over what I paid ($119 for the 240GB version), and runs near the speed of the Samsung 950 PRO, although benchmarks aren't consistent, still a lot of 'bang for the buck' & far greater than many other 'budget' offerings, such as WD & others, also backed by a 5 year warranty.

https://www.amazon.com/MyDigitalSSD-80mm-Express-PCIe-480GB/dp/B01MDRUXNZ?th=1

Anyway, the adapter linked above will keep most any SSD connected via PCIe port cooler, which will in turn, lead to a longer lifespan. Considering it's a sub-$15 component, great insurance for the drive.

I need to hurry & purchase another of the MyDigitalSSD BPX before the stock runs out, the 480GB this time!:lol:

Cat

 

[Venom_7]

After sometime using an adapter and testing it with some software (don't remember the name). There's a significant statistical difference favoring the PCI adapter NVM but it's only for my PC as the m.2 is over-dated currently (ASUS Z97-A mobo offers x2 the speed for the M.2 while newer versions offers more)