The truth about z620/z820 NVMe SSD boot

[DGroves]

Read The Factory Manual, or look at the inside cover of your z820, or look at the motherboards SATA/SAS ports and the answer will be obvious if you can discern colors

[41C]

The intel P3700 drive and its family members (P3600, P3500, 750-series and possibly P3520) will work as an NVME boot drives, as these contain the necessary bootloader codes for the Z820. The main benefit of the P3700, as I have installed, is its massive endurance rating compared to most SSDs - about 100x greater ... and that if you look carefully, you can sometimes find them cheaper than an equivalent SSD. 

However, there is no noticeable speed benefit and in most other respects, probably not worth the hassle. If doing this again, I'd just install an SSD (as a boot drive) on one of the 6Gb/s SATA ports and use the built-in SAS Controller to install 4 x 4TB enterprise-class SAS HDDs  (can find used ex-server examples with a rating of 2m hours MTBF) that will work just fine in a RAID arrangement.

[Mallaki]

Thanks DGroves. I did RTFM and now I know which ports are 6.0 GB/s. 😁

Having said that, this is so confusing it makes your head spin.  I re-read this thread several times now... With regards to installing NVMe SSD drive into my Z820 in PCIe slot x4, i decided to go with Micron 9200 series drive and StarTech U.2 to PCIe x4 Adapter.

I "hope" the last question before spending $$$ is to decide between:

• Micron 9200 MAX 1.6TB (MTFDHAL1T6TCU)
• Micron 9200 PRO 1.92TB (MTFDHAL1T9TCT)

[Mallaki]

Also, please explain why the SSD drive that has Read Speed around 550 MB/s perform slower on 3GB/s SATA vs 6GB/s SATA port?  

Why would that matter if drive maximum Read Speed is around 550 MB/s?

[DGroves]

please explain why the SSD drive that has Read Speed around 550 MB/s perform slower on 3GB/s SATA vs 6GB/s SATA port?

really? you actually are asking why a  3GBps port can't xfer as fast as a 6GBps port please use common sense.......................

SATA II (revision 2.x) interface, formally known as SATA 3Gb/s, is a second generation SATA interface running at 3.0 Gb/s. The bandwidth throughput, which is supported by the interface, is up to 300MB/s.

SATA III (revision 3.x) interface, formally known as SATA 6Gb/s, is a third generation SATA interface running at 6.0Gb/s. The bandwidth throughput, which is supported by the interface, is up to 600MB/s. This interface is backwards compatible with SATA 3 Gb/s interface.

[Mallaki]

My question was, why would it matter 3GB/s vs 6GB/s for a drive that is ONLY capable of Read/Write speeds of 500 MB/s

[DGroves]

go back and CAREFULLY reread my previous post, and if still unclear spend time googling/reading articles on differences between sata 3/6 speeds

[Mallaki]

OK, OK mr. DGroves. I guess what confuses me here is the big number 3GB/s and 6GB/s… NOW I know respectively they provide 300MB/s and 600MB/s throughput. If I would ask why are they called SATA 3GB/s and SATA 6GB/s? What does that mean 3GB/s ? what’s happening here at 3GB/s? Can this be answered in one/two sentences or does it require more intensive research and master degree?

Thank you in advance!

[SDH]

Sure.... it takes a bit of work and it comes down to a calculator and some time, and the difference between b and B, and some conversion factors.  The google knows:

Gb/s = Gigabits per second, while GB/s is Gigabytes per second
1 GB = 8 Gb... 1Gb = 0.125 GB... 1Byte = 8 bits... 1 bit = 0.125 Bytes 
Bits vs Bytes makes comparisons confusing, as does mixing Megabits and Megabytes with Gigabits and Gigabytes.
1 Megabit = 0.125 Megabytes
1 Mbps = 0.125 MBps = 0.125 MB/s

1 Gb Ethernet = 1 Gb/s
SATA II = 3 Gb/s, with the max bandwidth throughput of up to 300 MBps = 300MB/s
USB 3.0 = 5 Gb/s
SATA III = 6 Gb/s, with the max bandwidth throughput of up to 600 MBps = 600MB/s
10 Gb Ethernet = 10 Gb/s
USB 3.1 = 10 Gb/s
SATA Express = 12 Gb/s     (lost out to NVMe)

"600 MB/s is the same (roughly) as 6 Gb/s. 600MB/s -> 0.6GB/s -> 6Gbps. That last transition should actually be multiplied by 8, not 10, but you get the basic idea."

[SDH]

A thing many don't know is that the Z420/Z620/Z820 workstations are considered SATA III workstations but the choice of motherboard SATA ports used with a SATA III SSD (or SATA III HDD) can make a big difference.  In the Z620/Z420 there are only 2 motherboard SATA ports that are SATA III.  The Z820, of course, has added capabilities but you need to know what you're doing to get best performance.  For example, for our most common Z420/Z620 build I connect a SATA III modern boot/applications SSD to SATA port 0 and a larger modern SATA III SSD (or SATA III HDD) data drive to SATA port 1.  The slow optical drive is attached to a SATA II port, following the HP advice on drive attachment order in the manual, and this works fine for us.  That ODD is hooked to port 2, the topmost black port along the motherboard's front edge.  See bottom pic below.  The Z820 attachment order can get quite complex in comparison, and a topic for others.

Common simple fast driver ordering Z420 Z620