M.2

Hi all, Building a new rig after a fire. Anyone have experience with this new M.2 slot for OS drive? Good or bad? Worth the investment?
 
thanks
paul

Thanks for that well written reply!

If you use a M.2 Ultra SSD (PCIe x4) for your boot drive, you're wasting potential.

• A standard SATA-III SSD sustains ~520MB/Sec
• A PCIe x4 SSD sustains ~2500MB/Sec

500+MB/Sec is plenty fast for a boot drive.
Use the PCIe x4 SSD for disk-streaming sample libraries.
 

Thank you all for taking the time to chime in! Much appreciated

Paul

What I'm seeing is that many of these  new additions like M.2 are using an existing pipeline. IOW there isn't a dedicated M2 bus. As noted above some use the PCIe bus and some use SATA-3. In some instances this robs a useful slot or two or slows that speed down because you're tapping into that bus. In essence robbing Peter to Pay Paul as they say. An advantage in one area might mean a disadvantage in another area.
 
M2 was developed for laptops because it's a somewhat smaller form factor. Then later it came to be used on ATX motherboards. I would agree that I'm mostly seeing M.2 as a leech on a SATA-3 bus. 
 
I don't see any real advantage to M2 on a SATA-3 bus. There is advantage to an M2 on a PCIe bus. Raid-0 seems to be piggy backing two 520mbps lines together to get the 1000MB/sec. 
 
M.2 atPCIe x4 speed at 2500MB/second is pretty good. Certainly an advantage, but at what cost elsewhere? You're using 4 lanes of PCIe.
 
Seems to be a juggeling act depending on your other requirements and motherboard design. 
 

Also if you use the High end desktop boards, M.2 drives can actually get you more bandwidth, not that it is an issue as Jim notes. So on consumer boards, everything except the 1 or 2 PCIe 16x slots for video cards hang off the northbridge and all go over the same DMI bus to the CPU. All the rest of the PCIe slots, the M.2 slot, SATA, etc are all wired through it. However on HEDT boards, you can have up to 40 lanes of PCIe, so most or all of the slots including the M.2 slot are wired right to the CPU. The SATA controllers and all the rest are still wired to the northbridge.
 
All in all it just really doesn't matter though. Your computer has more internal bandwidth than you can realistically find a way to use. I've yet to see someone have issues because what they were doing was saturating the DMI bus or something like that.

Starise
Thanks Jim for that info!
 
My last build was the first example you used used syncraft. So it would have been an advantage to move up for more capability/speed. I was going for a mid level build. I have an M.2 slot on my mobo but chose not to use it since it it wasn't really an advantage in my case. I might try an HEDT in my next build. TBH I almost never adopt recent tech until I feel it is fairly safe. In this case it would have probably been ok to use the M.2 and I still might later on. 
my cpu was only 26 lanes I think, so I would have needed to upgrade to a more expensive cpu.
 
For anyone seriously considering an M.2 moving to 40 lanes/HEDT is probably something they want to do to take full advantage of the hardware.
 
The motherboard info I read basically said that it all would work, but might be slower which in the end probably isn't a factor for me.

We've got one particular client (Composer using similar setup)... and his machine yields 4000 stereo voices of disk-streaming polyphony via Kontakt.  Requires multiple SSDs (including PCIe x4)... but for most folks this isn't too limiting.   
 
Years ago (when plugin EFX/processing were first introduced)... we could only dream of the capabilities we have today.
 
The 5820k has 28 PCIe lanes.
Unless you're running two high-end video cards or multiple PCIe x4 SSDs, it's really not much of a limitation.