Questions regarding the M.2 SSDs and the T440s (And other new Haswell Lenovos)

So I'm waiting to pull the trigger on a T440s when it is finally available here in Canada (Hopefully within two weeks), and as per usual, I usually get a pretty low spec system and add parts (memory, storage) after the matter. My question is regarding the new M.2 SSD interface.

Currently on my W530, I am using the mSATA interface as my primare OS drive (128 mSATA), and I use the 2.5" SATA drive as a storage drive (Seagate 750GB). I do this because I like having my OS and paging on the fastest medium possible while keeping personal files and archival material separate. This also helps me a lot in terms of time-saving when I occasionally re-format.

To prepare for this, I'm reading the T440s user guide, and in every occasion, it's recommending NOT to use the M.2 SSD interface as the boot-up drive and insists that this only be used for HDD caching, supplementing performance for what should be the boot-up HDD, which is the 2.5" SATA bay.

So, my question is two-fold. Most importantly, will booting up with the M.2 interface even work? (i.e., is it a BIOS think where they won't even let you select the M.2 interface as a boot-up drive) If so, I understand there are different sizes (physical dimensions) of M.2 drives - Is the T440s compatible with all of them?

Thanks in advance!

Larry

 

The M.2 slots in the T440 series are 42mm, which is the smallest for M.2 SSD cards and the highest-capacity one currently available is the 128GB version from MyDigitalSSD. It is not the fastest SSD out there, but fast enough IMO (and faster than the Intel 310 mSATA drive I currently use in my T420). Intel supposedly has a 120GB model coming out soon. Not sure we'll see anything with a higher capacity than these two for some time, though considering mSATA cards are only 9mm longer and already come in 512GB sizes I'm sure eventually small M.2 cards will catch up.

I'm also curious about using these as boot drives. It can be done, I plan to do it and many people seem to have done it, but it reportedly requires changing the boot mode in the bios to "legacy", so you lose the slight speed advantages of the newer UEFI mode when waking from sleep/hibernation. No idea if there are any other disadvantages of using an M.2 SSD as a boot drive, but from what I remember mSATA drive were also originally marketed as purely cache drives (and sometimes still are).

One thing to note with the T440s is it can be configured with three M.2 slots (one listed as "additional expansion option") or two M.2 slots including one for double-sided cards.

 

Small correction: It is not the smallest M.2 formfactor. There is also the 30mm formfactor, which also could be used for Cache SSDs.

 

I doubt we'll ever see 30mm M.2 SSDs, though I'm no expert and am often proved wrong

 

Thanks for the responses, guys.

PIPSpeak. Are you guys sure about losing the UEFI functionality? After doing some googling, this video claims that it is booting off of an M.2 SSD and it looks like a UEFI boot screen.

Also, I am currently running UEFI when booting up with my mSATA - That's probably doesn't say too much though, as M.2 and mSATA might work differently.

 

I've also seen that video but no idea what his setup was. The only 42mm M.2 SSD of any size currently available afaik is the MyDigitalSSD 128GB and by all accounts this requires legacy boot to work in lenovos. Whether this is a "feature" of Lenovo machines in particular, that card in particular, or something to do with how M.2 cache-drive slots are configured in general, I'm not sure. Perhaps others could chime in.

 

Also, with these new Haswell based laptops, can anyone figure out if these systems do come with 3 M.2 slots, are any of them connected to the PCIe bus, or are they all SATA controlled?

 

Hey I'm waiting for it to show up on .ca also haha...

If it has UEFI, booting off mSATA should work. It takes some effort to get it setup though:

Rod Smith - Managing EFI Boot Loaders for Linux
Arch Wiki -https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface#UEFI

rEFInd provides a boot option menu in addition to what you get when you spam f8 or del during POST (USB, PXE, SDHC cards...)

All the boards I've seen that use UEFI allow you to opt-out and use the "legacy" option. You can just setup the boot order of your devices that way if you want. But, I haven't seen screenshots of the BIOS on these units yet.

I'm also wondering how many storage controllers are on these machines as well.

 

I'd like to be able to keep UEFI - I'm also wondering if M.2 FF SSDs operate in the same way as mSATA, or if they are architecturally different.

 

Ok now I share your concern:

Samsung XP941 NGFF M.2 PCIe SSDs in RAID 0 - Worlds Smallest SSD Combination Hits 2GB/s | The SSD Review

In the comments he mentions, "...enabling a PCIe card as a boot drive means that it must be recognized before the system bios in a separate BIOS..."