Confusion over SATA3/PCIe SSD or sata3 PCIe adapter

[Daniel Cook The First!]

Dear all,
Hi, this is my first post and I apologise if this has been covered. I did look but couldn't see what I needed but this could be my lack of knowledge!
Anyway.
I have a sooped up MacPro 5,1.
(2 x 3.46 GHz 6-Core Intel Xeon and a NVIDIA GeForce GTX 780)
Currently it has this in a sled in a SATA 3 hard drive bay:
https://www.amazon.co.uk/Samsung-inch-Solid-State-Drive/dp/B00P738MUU
Specs are:
540 MB/s read, 520 MB/s write.

In the ever present desire to go faster I have 2 questions I think:
1. If I buy a Sata3 to PCIe adaptor sled and plug it direct, will I see a performance increase?
2. If I wouldn't see a performance increase, what is the best alternative, money no object. (I don't know what NVME is but am happy to consider if it's compatible as a boot drive/affordable!).

Thank you in advance for any input.
Best,
Dan

 

[h9826790]

Dear all,
Hi, this is my first post and I apologise if this has been covered. I did look but couldn't see what I needed but this could be my lack of knowledge!
Anyway.
I have a sooped up MacPro 5,1.
(2 x 3.46 GHz 6-Core Intel Xeon and a NVIDIA GeForce GTX 780)
Currently it has this in a sled in a SATA 3 hard drive bay:
https://www.amazon.co.uk/Samsung-inch-Solid-State-Drive/dp/B00P738MUU
Specs are:
540 MB/s read, 520 MB/s write.

In the ever present desire to go faster I have 2 questions I think:
1. If I buy a Sata3 to PCIe adaptor sled and plug it direct, will I see a performance increase?
2. If I wouldn't see a performance increase, what is the best alternative, money no object. (I don't know what NVME is but am happy to consider if it's compatible as a boot drive/affordable!).

Thank you in advance for any input.
Best,
Dan

I assume you mean the SSD now is in a SATA 2 bay.

1) Yes on sequential read / write, no for everything else.

2) I won’t recommend you go NVMe at your current knowledge level. It won’t boot natively without firmware hack. On the older OS, you can’t even use it as data only drive. Of course, you can study and learn, but nowhere near plug and play (if you don’t know what you are doing).

 

[pl1984]

Here is a list of the various technology from slowest to fastest:

• PCIe SATA 3
• PCIe M.2 AHCI
• PCIe M.2 NVMe

The latter is the ideal but, as already mentioned, is the least compatible (for the cMP). Unless you're performing a lot of sequential reads / writes moving to a PCIe M.2 solution probably won't benefit you much, if at all.

 

[Daniel Cook The First!]

Thanks for your help.

Sorry thought the 5,1 was SATA3, obviously it's SATA2. So yes in answer, I have the SSD in a sled in a SATA2 conection.

I assume a PCIe M.2 AHCI is one of these where the SSD is on the card instead of an SSD on a PCIe adapter?
https://www.ebuyer.com/766048-samsu..._QTra7r-uJQn-3H8jL2sQMf4JA5R3oCBoCOqoQAvD_BwE

For 1TB they're expensive so not an option.

Considering a PCIe adapter like this is so cheap I think I'll try it:
https://cpc.farnell.com/akasa/ak-pc...F0W48Iz_-XhhbEn3ZhS-nCJ70T2-CnXhoCm30QAvD_BwE

I'm doing lots of read/write so you think I'll see an increase over current set up?

Thank you.
Dan

 

[pl1984]

Thanks for your help.

Sorry thought the 5,1 was SATA3, obviously it's SATA2. So yes in answer, I have the SSD in a sled in a SATA2 conection.

I assume a PCIe M.2 AHCI is one of these where the SSD is on the card instead of an SSD on a PCIe adapter?
https://www.ebuyer.com/766048-samsu..._QTra7r-uJQn-3H8jL2sQMf4JA5R3oCBoCOqoQAvD_BwE

For 1TB they're expensive so not an option.

Considering a PCIe adapter like this is so cheap I think I'll try it:
https://cpc.farnell.com/akasa/ak-pccm2p-01/adapter-card-m-2-ssd-pcie-x4/dp/CS30342?mckv=s0E1QR1jF_dc|pcrid|224690506549|kword||match||plid||slid||product|CS30342|pgrid|50784124721|ptaid|pla-374157605172|&CMP=KNC-GUK-CPC-SHOPPING&gclid=CjwKCAjwwdTbBRAIEiwAYQf_E3ChmKLjBmC6G3d5JFnsnVF0W48Iz_-XhhbEn3ZhS-nCJ70T2-CnXhoCm30QAvD_BwE

I'm doing lots of read/write so you think I'll see an increase over current set up?

You are correct that M.2 is the card based SSD and is useable in an adapter which plugs into a PCIe slot. There are two different types of M.2 SSDs: AHCI and NVMe. Of the two AHCI can be used as a boot drive in more systems than NVMe but is roughly half the speed of NVMe.

How each type will benefit you depends on the type of disk access you typically perform. For many users their disk access consists primarily of random reads / writes. Unless you know otherwise it's likely you fall into this category. If this is the case it's unlikely replacing your existing setup with something faster will provide you any noticeable gains. Take booting your system as an example. Using the following chart (credit to h9826790):

You see boot times with your current set up (represented by the bar on the far right) is a mere half second slower than the M.2 AHCI SSD (represented by the second bar from the left). IME boot and application load times are where the majority of consumers benefit from an SSD.

Where the PCIe AHCI and NVMe based solutions really excel is in sequential reads / writes. It is this number which you typically see provided as it provides a stark comparison (credit to crjackson2134):

This is a top of the line PCIe NVMe drive which is providing 2,215MB/sec write speed and 2,909MB/sec read speeds...much faster than the maximum theoretical speed your solution can provide (300MB/sec limited by the Mac Pro's SATA ports). It's been my experience PCIe AHCI solutions provide about half the NVMe speeds...which is still well above any SATA speed (let alone the SATA-II in the Mac Pro). If you perform a lot of sequential reads / writes then either M.2 solution would provide a noticeable performance increase.

But if you're not performing a lot of sequential reads / writes then M.2 solutions are unlikely to provide any noticeable benefit over what you currently have.

EDIT: Here is a summary of a SATA SSD (840 EVO, left image) versus an NVMe SSD (970 Pro, right image) (credit to handheldgames:

The random information are rows two and four. On row two you can see the SATA SSD provides 180MB/sec random reads and 10.74MB/sec random writes. Both of these are well within the 300MB/sec of the Mac Pro's SATA-II connection. The same row for the NVMe based solution, using a newer, higher end SSD (compared to the SATA SSD) provides 369.4MB/sec random reads and 68.22MB/sec random write speed. The 369.4MB/sec speed does exceed the Mac Pro's 300MB/sec SATA-II connection but does not exceed a SATA-III connection. Would this extra 69.4MB/sec be noticeable? I suspect it would not (recall these are benchmark numbers, real world is likely to be lower).

My recommendation would be to stick with your current configuration for boot / application launch and, if you want higher speed for sequential disk access (which is primarily going to be your data) then buy a PCIe M.2 solution for your data. The SATA solution will allow you to boot your cMP and the M.2 solution will provide the higher throughput for data access (which doesn't need to boot).

 

[Daniel Cook The First!]

Hi, amazing response, thank you very much! I'm going to take your advice and give it a go. Thanks again, Dan