Samsung 970 EVO or PRO NVMe for cMP?

[fhturner]

Some questions about the latest Samsung 970 SSD blades:

1. Is there much to gain, aside from some write endurance, on our Mac Pro towers by choosing a Samsung 970 PRO over the EVO, assuming the 500/512GB or 1TB capacity fills our needs? I realize there's some add'l performance in the PRO, but if I've been extremely pleased w/ an AHCI SM951 or SSUBX (or heck, XP941/SSUAX for that matter), and since the PCIe 2.0 bus** is going to be a limiting factor beyond a certain point anyway, would I really want to pay $300 more for a 1TB PRO, for example?

**= Assuming we're connecting w/ an inexpensive x4 adapter, not a fancy HighPoint 7101A that could spread the extra perf across 16 lanes.

2. I'm okay w/ injecting the NVMe driver into the firmware (from what I've read!) to make this work as a boot drive, especially to open up more, newer, and less expensive SSD options. But if I do this for a client's machine, any reason it couldn't work as long as I warned him not to update firmware on his own unless he chats w/ me about it (or Apple finally starts including in stock bootrom)?

Thx,
Fred

 

[tsialex]

Some questions about the latest Samsung 970 SSD blades:

1. Is there much to gain, aside from some write endurance, on our Mac Pro towers by choosing a Samsung 970 PRO over the EVO, assuming the 500/512GB or 1TB capacity fills our needs? I realize there's some add'l performance in the PRO, but if I've been extremely pleased w/ an AHCI SM951 or SSUBX (or heck, XP941/SSUAX for that matter), and since the PCIe 2.0 bus** is going to be a limiting factor beyond a certain point anyway, would I really want to pay $300 more for a 1TB PRO, for example?

**= Assuming we're connecting w/ an inexpensive x4 adapter, not a fancy HighPoint 7101A that could spread the extra perf across 16 lanes.

2. I'm okay w/ injecting the NVMe driver into the firmware (from what I've read!) to make this work as a boot drive, especially to open up more, newer, and less expensive SSD options. But if I do this for a client's machine, any reason it couldn't work as long as I warned him not to update firmware on his own unless he chats w/ me about it (or Apple finally starts including in stock bootrom)?

Thx,
Fred

I don’t personally own 970 series SSDs but I’ve tested and installed some.

The basic difference beyond warranty, seems the write buffer. 970Evo downgrades write performance once the buffers saturate. If your use case don’t saturates it, you will not see diffs between the drives. But if you are dependend on long continuous writes, you will notice a step drop in write performance.

NVMe for boot will not be a problem if you don’t update your firmware. Once updated, the NVMe DXE is wiped.

 

[fhturner]

The basic difference beyond warranty, seems the write buffer. 970Evo downgrades write performance once the buffers saturate. If your use case don’t saturates it, you will not see diffs between the drives. But if you are dependend on long continuous writes, you will notice a step drop in write performance.

Yeah, read a little bit about that...something about using SLC buffer for the first 4GB of write ops, then up to a certain amount more, depending on size of the drive. "Intelligent TurboWrite" they call it. Sounds like the EVO would be fine for most uses, but that the PRO is more in line w/ the SM951/SSUBX blades I'm most familiar with that use MLC instead of TLC and do not rely on buffering for their high throughput. Sound correct?

Another question that comes to mind: If I wanted to use an NVMe SSD on my own machine, where I need to occasionally dual boot into an earlier system to use FCP 7, is the BootROM NVMe DXE injection sufficient for that, or do you also get into needing a software driver in the (older) OS too?

 

[tsialex]

Yeah, read a little bit about that...something about using SLC buffer for the first 4GB of write ops, then up to a certain amount more, depending on size of the drive. "Intelligent TurboWrite" they call it. Sounds like the EVO would be fine for most uses, but that the PRO is more in line w/ the SM951/SSUBX blades I'm most familiar with that use MLC instead of TLC and do not rely on buffering for their high throughput. Sound correct?

Yep

Another question that comes to mind: If I wanted to use an NVMe SSD on my own machine, where I need to occasionally dual boot into an earlier system to use FCP 7, is the BootROM NVMe DXE injection sufficient for that, or do you also get into needing a software driver in the (older) OS too?

You can use some NVMe SSDs with Sierra, 4K sector ones, someone did a list here sometime ago. High Sierra support both sector sizes, 4K and 512bytes per sector. Samsung drives with 512bytes per sector works only with High Sierra. So you have to use another disk for older MacOS.
[doublepost=1535552639][/doublepost]This post has more info about sector size and macOS support #13