MP 7,1 Apple SSD for Mac Pro: kind and quality?

[LeonPro]

I can't seem to find a definitive answer of what kind of memory sticks Apple is using SPECIFICALLY for the Mac Pro 7,1. Who is the manufacturer and are they using MLC or TLC?

Also since these are installed in pairs for 1TB and above, does this mean it's using RAID 0? And if so, why is the read/write speed slow compared to a true RAID 0 when using 2 sticks that can achieve 6,000 MB/s?

 

[ondioline]

The only definitive information I've seen is from the NAND in the iMac Pro, which is the same form-factor and configuration. They use SanDisk Ultra 3D TLC NAND.

Additionally it's functionally RAID 0. The two SSDs are connected to the T2 through two 4x PCIE 3.0 interfaces. It's not really all that slower than NVME drives in RAID 0.

 

[tsialex]

I can't seem to find a definitive answer of what kind of memory sticks Apple is using SPECIFICALLY for the Mac Pro 7,1. Who is the manufacturer and are they using MLC or TLC?

Also since these are installed in pairs for 1TB and above, does this mean it's using RAID 0? And if so, why is the read/write speed slow compared to a true RAID 0 when using 2 sticks that can achieve 6,000 MB/s?

Don't focus to much with bandwidth, it's a totally misleading metric - the new megapixel.

You will only achieve the full bandwidth available when cloning disks or moving enormous files to another equally fast disk. Most, if not almost, the time working you are bound by 4K disk access and it's where you have to look at benchmarks, not total bandwidth that you almost never will achieve in real life.

This total focus on bandwidth are even changing NVMe designs, some drives are now tuned for benchmarks, not real work. HP was caught doing that recently with EX950, the original firmware had wonderful numbers with sequential transfers, but the drive was a dog at some 4k metrics. A perfect blade for benchmarking sequential transfers, sh_t for doing real work.

Another thing, even if a drive has magical write metrics on benchmarks, what is the real write speed after the SLC cache is full? It's another thing constantly overlooked and one of the real problems that people doing video have. For any TLC drive, you are choked the moment the SLC cache is full.

 

[LeonPro]

Thanks all.

@tsialex appreciate the further info. I was hoping RAID 0 would help this issue a bit by splitting the write time between at least 2 drives and also doubling the SLC cache as a result. For the Samsung 2TB 970 EVO Plus - unless Samsung is doing more creative marketing - they say they have a dynamic SLC cache buffer that can portion from 6GB and up to 78GB if needed. If this is true, that shouldn't bog down even video editors like myself in real-world use per stick. Let alone if these were in RAID 0?

 

[AidenShaw]

I was hoping RAID 0 would help this issue a bit by splitting the write time between at least 2 drives and also doubling the SLC cache as a result.

This statement seems to assume that each blade on the T2 is an SSD, and the T2 is RAIDing them.

The blades are just dumb flash nvram - the "SSD" is based in the T2 controller, and the blade(s) is(are) simply persistent store for the T2 controller.

The allocation of storage to SLC cache would be the responsibility of the T2 controller. The blades (or commercial SSDs for that matter) do not have a region of SLC flash dedicated for cache. Instead, the "SLC cache" is a section of TLC flash that is used in single-bit mode. https://www.atpinc.com/de/blog/what-is-SLC-cache-difference-between-Dynamic-Static-SLC-cache

 

[LeonPro]

Yes, I take that since there are two 2TB Apple sticks and I am seeing 4TB in total then Apple (via T2) is doing a RAID 0?

As for the third-party sticks, I do get they are using the same allocated memory as SLC cache since it is dynamically changing on demand. Appreciate the clarification though.

 

[AidenShaw]

Yes, I take that since there are two 2TB Apple sticks and I am seeing 4TB in total then Apple (via T2) is doing a RAID 0?

The "ID" in "RAID" means "Independent Disks" - there are no disks connected to the T2 controller. Don't use disk terminology to describe Apple's proprietary T2 setup - it's not appropriate.

Even low cost flash thumb drives often stripe across memory chips for better performance - but that's not "ID".

 

[LeonPro]

I mean by that definition

The "ID" in "RAID" means "Independent Disks" - there are no disks connected to the T2 controller. Don't use disk terminology to describe Apple's proprietary T2 setup - it's not appropriate.

Even low cost flash thumb drives often stripe across memory chips for better performance - but that's not "ID".

Oh darn I guess the definition of "independent" is confusing then as these are clearly independent physical disks. And by definition of memory chips striped together as one - isn't this true across all memory sticks, no?

In any case, if two independent physical disks joined as one by Apple isn't RAID by its action of actually striping together and doing RAID 0 style - then what should it be termed as then? I'm genuinely curious why this shouldn't be called a type of RAID even if Apple want's to call it, umm, Apple T2 RAID if they have to?

 

[DeltaMac]

You are forgetting that the flash nvram connected to the T2 controller are not disks, per se.
The "disk" is created/controlled by the T2 chip.
As AidenShaw pointed out, the NVRAM chips do not have on-chip controllers, so are not SSDs, nor are they "disks", just NVRAM. Not independent. You might call them "inter-dependent" (?), but you probably can't use the term RAID to describe how that NVRAM is utilized by the T2 chip.

 

[LeonPro]

You are forgetting that the flash nvram connected to the T2 controller are not disks, per se.
The "disk" is created/controlled by the T2 chip.
As AidenShaw pointed out, the NVRAM chips do not have on-chip controllers, so are not SSDs, nor are they "disks", just NVRAM. Not independent. You might call them "inter-dependent" (?), but you probably can't use the term RAID to describe how that NVRAM is utilized by the T2 chip.

Ah, I believe I got it now and sunk through my thick skull!

The T2 being the controller plus the NVRAM chips make up the "disk" per se.

As compared to an NVMe SSD stick which is made up of the chips and the controller which are all self-contained and therefore is an independent disk in itself.

 

[IA64]

You are forgetting that the flash nvram connected to the T2 controller are not disks, per se.
The "disk" is created/controlled by the T2 chip.
As AidenShaw pointed out, the NVRAM chips do not have on-chip controllers, so are not SSDs, nor are they "disks", just NVRAM. Not independent. You might call them "inter-dependent" (?), but you probably can't use the term RAID to describe how that NVRAM is utilized by the T2 chip.

So what's the advantage of this setup afterall? They could have gone with one NVRAM stick instead of two in the MP7.1 no?

 

[DeltaMac]

I think the better question would be: What does the T2 chip do with the NVRAM...?

Maybe it is nothing more than "two chips are cheaper than a single chip of the same size."
Maybe the T2 controller uses the two chips, resulting in a parallel access to the two chips, very much the same goal as a RAID configuration (speed and/or security), but without the need to have device controllers on each chip.

 

[s66]

The Apple provided proprietary storage module(s) in a MP7,1 are not standard SSD modules available elsewhere.
They are merely NAND storage controlled by the T2 chip and the modules are married to that T2 controller.

You can buy other modules from Apple nowadays and replace them using a non-trivial procedure to remarry the T2 to the storage modules.

FWIW: the MP7.1 cannot boot without these modules functioning as its firmware is stored on these storage modules.

To add storage solutions from other vendors: you need to buy standard SSD modules (e.g. M.2 or U.2 or so) and connect them via a PCIe 3.0 card in the MP.
You can boot from these if you want to.

Ref:
- https://support.apple.com/en-us/HT210626
- U.2 card: https://www.sonnettech.com/product/fusion-dual-u2-ssd/overview.html
- M.2 modules and cards are discussed plenty in this forum