Hoping that someone can help me. I'm looking at upgrading my pc and wanted to use the new M.2 socket to save space. I've been trying to wrap my head round this, got dizzy, fell over and am not sure if I am better informed or not. As I understand there are 2 types of M.2 SSD, based on PCI-e and SATA3 connections. The PCI-e M.2 SSDs can reach higher speeds and the SATA3 ones would perform similar to a standard 2.5" SSD. Is this correct? I'm totally lost on the whole 'Key' thing so any idiot proof explanation would be very welcome. Does anyone else have/use an M.2 SSD? I've initially chosen the following parts: Asus H97I-PLUS (apparently supports both types of M.2 SSD. Is this possible?) Crucial M550 256GB M.2 SSD (I think this is a SATA3 type M.2 SSD) Are they compatible? What has me worried is, during my google-fu training session, I found a post on the crucial forum stating that the Maximus Hero VII is only compatible with PCIe devices and so the M550 is not compatible. Why would ASUS have two different setups on their motherboards?
Thanks for the quick reply. I'll email Asus in the morning about compatible M.2 SSDs. There seems to be a lack of clarity from both motherboard and SSD manufacturers about this tech. Crucial don't even have their M.2 SSDs for sale on their own website. I may have to rethink my whole upgrade and wait until these SSDs are more widespread.
There's absolutely no reason why the Crucial shouldn't work, as there's both pcie & sata M.2 drives in the compatibility list;so it's clearly wired for both. Well, the controller & qty of nand are irrelevant... Well otherwise, buying a 2.5" sata SSD then you'd have to check compatibility for everything - whereas, instead, sata is just sata. That said, it is always worth checking which a board can do though as there are lower end boards that can be wired for pcie only... ...& i believe that some netbooks/laptops can be wired for sata only. Oh, & similarly, you can get pcie M.2 slots with varying numbers of lanes - normally either 2 or 4...
I suppose waiting would be the sensible thing to do. I just need to try harder to fight the upgrade urge. The fact that they state compatibility for both PCIe and SATA drives is what had me confused as the SATA M.2 SSDs I have found have been B&M Key devices. What I need to find out now is whether the board M Key connector is compatible with B&M Key SSDs (not holding my breath here though). I could always go for the Plector M6e which is M Key and PCIe so should be ok, but is £60 more. Will using a PCIe SSD impact on the number of lanes available for the graphics card on an ITX motherboard? Edit: OCUK has a 256GB Plextor M6e for £155 which is a better price, any opinions on whether this is compatible?
Forgot to add that I tried to contact Asus about this but their Contact Us page is set up for people who have bought products (serial number is a required field).
If money is no object i would get a Samsung XP491, going on the following it's compatible with the H97I-Plus and out of all the M.2 drives it's by far the fastest.
That was a very good read, thanks for the link. It cleared up one point at least. The Plextor m6e is a B&M Key so these are compatible with the stated M Key connector on the Asus board. I'm assuming that the motherboard would run the SSD at PCIe x2 speeds which is plenty fast enough but it is still not clear if this affects the PCIe lanes available to a graphics card on an ITX motherboard. The worrying thing pointed out in that article was the operating temperatures of the controller chips on these new SSDs. I think I'll hold off until the tech is more mature and the temperature issue has been resolved. Thanks for everyone's input.
Ok so I have returned full circle. As far as I can tell the Asus H97 motherboard will accept B&M key M.2 SSDs (Corky's link shows the Plextor m6e works). Asus states that the M.2 connector will work with both PCIe and SATA M.2. This leads me to believe that the Crucial M550 will work. I'm assuming the temperatures measured in the article are for the PCIe controller and this may not be an issue with the SATA M.2 versions. This is driving me nuts.
AFAIK the M.2 slots on all H97, Z97 boards use the PCIe 2.0 lanes, so the graphics card would have exclusive use of the 16 PCIe 3.0 lanes, these lanes are directly provided by the CPU, the 16 PCIe 2.0 lanes are provided by the chipset. I believe so. If you are considering a SATA based M.2 wouldn't a normal SSD be the cheaper, less hassle choice?
Yes it would, but I'm looking to put this in a small scratch build case so removing the need to find space for a SSD simplifies the design a little. It will also reduce the number of cables I need to use making the case tidier.
That makes sense. Yes i believe the temperature issues are only seen on the PCIe controller of M.2 drives, a SATA M.2 drive shouldn't get any hotter than a standard SSD drive, as essentially it's the same thing just in a different package.
Well I've just placed the order so we'll find out soon enough. i7 4790s, H97I-Plus and Crucial m550 256GB M.2 This is a very expensive habit lol
This is almost correct. The 16 pcie 3.0 lanes, from the cpu, are solely used by the full length pcie cards - of which there's obviously only 1 on the board in question - however there are only a max of 8 pcie 2.0 lanes via the H97 or Z97 chipsets, not 16. Looking at the spec of the board however, only 2 of the pcie 2.0 lanes are assigned to the m.2 socket... ...so 'if' the OP had gone for a pcie one, they wouldn't have seen huge amounts in the way of any gain from the Samsung - as that's designed for 4 lanes, so the bandwidth would be halved. You'd expect the m.2 sata versions to run hotter than a 2.5" drive with the same controller & spec if for no other reason than the cases of the 2.5" drives usually are employed as a large heat sync... ...however they will be noticeably cooler than the pcie ones. The problem with those tests though, are that they're run on an open test bench with (effectively) no air flow. Now, that's not to say that, in say a passively cooled system, this couldn't potentially be a problem - however with a reasonable amount of airflow then it's not inherently an issue. Well, for example, the heat sinks on processors on decent raid cards can easily reach in excess of 100C without a bit of air getting to them & can overheat, but clearly they're not impossible to use with a modicum of air flow & the components around the chip are obviously designed to operate at high temps... (in a low airflow case, even a crappy pcie exhaust fan below the heatsink is typically sufficient for cooling a raid card) ...so, whilst the pcie m.2 cards shouldn't be hitting that kind of temp, it's primarily an issue with the testing setup not providing reasonable cooling - as naturally all kind of components in a PC run hot & need either specific cooling (ie a CPU/GPU fan) or airflow.
You're absolutely correct about those ASRock boards using pcie 3.0 lanes - they're not a brand i hugely take much notice of. What's below is about raising questions - not saying that i'm correct as i don't use SLi or CF... Without looking at the ASRock boards in particular though, just the no of lanes remaining, with gfx cards then why couldn't there be a plex chip to split 8 of the remaining lanes into two 8x slots? Well, that's how many people run multi-card setups anyway - &, whilst more efficient than two separate 4x\4x slots, they're obviously not actually running at 8x\8x - given that it's only the speed until you get to the plex chip. Without a plex chip though, i believe that there's an artificial limitation that NVidia have created with sli that prevents it working with one or more of the cards in 4x slots, rather than that it would necessarily be dreadful... ...however that limitation isn't there with AMD cards. ignoring the limitation for SLi though, i'm then curious as to what it is that's so shonky about 4x pcie 3.0? Well, naturally it has the same bandwidth as 8x pcie 2.0 - & no one ever said that you shouldn't use CF or SLi with a pair of them. i accept that it would depend on the card - so, ttbomk, a single mid range card would lose maybe 1 or 2% in fps on each step downwards from 16x to 8x to 4x pcie 3.0 - whereas i'd expect there to a greater decrease on top end cards going from 8x to 4x. Moving on a stage, with CF, i also believe that you can successfully CF between pcie 3.0 & pcie 2.0 slots - so you 'could' have a board with three pcie 3.0 4x slots & one pcie 2.0 8x slot - giving quad CF with all of them running at the same speed. Yeah, just thoughts as, whilst not ideal that there are so few lanes in total, it doesn't immediately appear to be a make or break thing for either SLi or CF.
As you said, performance difference is minimal, but NVIDIA has that limitation. http://www.asrock.com/mb/Intel/Z97 Extreme9/ is the solution for both of the problems. It's a 225 euro Z97 board with PLX chip, Ultra M.2 slot and also standard M.2 slot.
