Choosing an M.2 drive, double the size or double the speed? - Page 1
Forum section: electronics / general

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 29, 2016, 04:53:48 am
content: I'm finally getting around to the last thing I need to do to count my upgrade as completed, but seeing as M.2 is relatively new I know I'll be revisiting this in about a year when prices have dropped and performance and capacity have increased I've set myself a limit of around £100 for the drive. The two options I'm considering are a 256GB Samsung SM951 that claims up to 2150MB/s read and 1200MB/s write and a 512GB Samsung PM951 that's roughly half those speeds. The M.2 drive will only be used for OSs and select programs and games. Others opinions on what they would go for and why would be very much appreciated.Thanks

author: Skimask
author_rank: Super Contributor
timestamp: March 29, 2016, 05:07:16 am
content: 256GB - those speeds are burst speeds, not sustained. Good luck getting those kinds of speeds over the bus unless reading/writing to the drive is ALL you're doing...in other words, running speed tests.512GB - double the space (a quantifiable number) and half the speed of the other one (half of an un-quantifiable, un-repeatable number is still an un-quantifiable, un-repeatable number).And in a year, the 256GB model will be 1/2 the price it is now (ok, maybe not half...) if the 512GB drive isn't fast enough.

author: Halcyon
author_rank: Unknown
timestamp: March 29, 2016, 05:28:39 am
content: Depends what you're using it for. Being an M.2 drive, I assume you're using it in some embedded application or mini-PC? That being the case, I doubt your drive will be the bottleneck in terms of transfer speed. If you're not doing a lot of reading/writing (such as with a home theatre application where once the system is loaded into RAM, disk usage is minimal), then I wouldn't be too bothered on advertised speeds.If space is what you need, buy the biggest you can afford. If long-term reliability and/or industrial applications are more important, consider a SLC (Single Level Cell) model vs. the more common MLC (Multi Level Cell) type flash. SLC is far more expensive but can endure far more program/erase cycles than MLC flash chips and are usually designed with "industrial" products in mind so operational temperature range is greater. You will suffer slightly lower write speeds with SLC however. MLC is the stuff you find in most consumer SSD's and USB flash drives.To give you an idea of the price difference, you can pick up an 8GB Addonics branded SLC M.2 flash drive from Techbuy for AUD$132. For $20 less, you can buy a 64GB MLC M.2 flash drive from the same manufacturer.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 29, 2016, 05:57:06 am
content: Quote from: Halcyon on March 29, 2016, 05:28:39 amIt's going into my "budget high end" main home desktop/gaming system. Skylake i7 (not the unlocked one), 64GB of ram, 1TB SATA SSD, and a 980ti.

author: Halcyon
author_rank: Unknown
timestamp: March 29, 2016, 05:59:05 am
content: Quote from: Mechanical Menace on March 29, 2016, 05:57:06 amSeems like an awful lot of RAM! Anyway, that's another issue. What sort of motherboard? What is the M.2 drive doing that the SATA Hybrid/SSD isn't?

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 29, 2016, 06:29:16 am
content: Quote from: Halcyon on March 29, 2016, 05:59:05 amYeah, but got it as cheap "bought and returned" and 16 would have cost me.QuoteA cheap and cheerful Gigabyte Z170XP-SLI, it's not meant to be the best overclocking MoBo but I won't be doing that anyway. The M.2 port is SATA and 4 lane PCIE gen3 compatible. The M.2 drive would be pretty much dedicated to OSs except for the odd game and program that I find loads too slow from the SATA SSD and is due to disk accesses. Everything else, including swap partition and paging file will be on the 2.5" drive.Quote from: blueskull on March 29, 2016, 06:22:00 amI'll read up on that but that's probably settled it lol.Thanks everybody.

author: Halcyon
author_rank: Unknown
timestamp: March 29, 2016, 06:31:33 am
content: Quote from: blueskull on March 29, 2016, 06:22:00 amYeah there is a Triple Level Cell flash now. It's cheaper but more prone to errors and slower than SLC and MLC. You'll find that some manufacturers of TLC flash drives will increase the amount of memory actually on the device (not what's available to the user) and tweak their wear-leveling algorithms to compensate for increased failure rates.Quote from: Mechanical Menace on March 29, 2016, 06:29:16 amI honestly wouldn't worry about R/W performance. Just get yourself a decent brand-name MLC M.2 drive. If you want a "happy medium" between SLC and MLC drives, there are eMLC (Enterprise MLC) drives out there, but I think they mostly have a wider operational temperature range. Also, with that amount of RAM, I'd also seriously consider disabling the swap/page file completely.I just recently bought myself a 120GB Kingston M.2 SSD for AUD$88

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 07:01:32 am
content: Lol at "burst speeds". There isn't cache, although the SM951 does thermal throttle after continuous use at those speeds.Do I stuck some small heatsinks on it. Hides the ugly green PCB on an otherwise black-white colour theme.Why are you not considering the 950 Pro? SM951 and PM951 are OEM not supported by Samsung. 950 is.Also if you're using Windows 8 or 10 you should get the NVMe protocol and not AHCI protocol - much better latency.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 29, 2016, 07:08:44 am
content: General rule of thumb nowadays is that with 8GB RAM or more, you don't even need a swap partition. To make poorly coded apps happy (those that blindly check for swap), you can use zram to effectively make "compressed RAM drive swap". Also make good use of tmpfs for temporary directories.I actually upgraded my PC to 48GB recently in order to run more VMs.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 29, 2016, 07:33:47 am
content: Quote from: RGB255_0_0 on March 29, 2016, 07:01:32 amThe 950 Pro is £140, I've been offered the SM951 for £75 and the PM951 for £85 and I'm only expecting this to last a year before I upgrade it so the 2 or 1 year warranties is enough.Basically I'm being tight.

author: Halcyon
author_rank: Unknown
timestamp: March 29, 2016, 07:45:07 am
content: Quote from: Mechanical Menace on March 29, 2016, 07:33:47 amThen go with the cheapest.

author: Philfreeze
author_rank: Regular Contributor
timestamp: March 29, 2016, 12:02:54 pm
content: Quote from: Mechanical Menace on March 29, 2016, 05:57:06 amHad to fix it for youWhen it comes to SSD storage always buy the slower/smaller one. In two year you will get the one you originally wanted to buy for half the price or less and you will feel stupid if you haven't really used the additional storage/speed.

author: Monkeh
author_rank: Super Contributor
timestamp: March 29, 2016, 12:11:09 pm
content: Quote from: RGB255_0_0 on March 29, 2016, 07:01:32 amYes, there is.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:36:09 pm
content: Quote from: Monkeh on March 29, 2016, 12:11:09 pmThere is a buffer, but no power loss protection, hence why these are not classified as Enterprise grade. But these speeds are not burst write/reads. These are sequential read and writes.

author: XOIIO
author_rank: Super Contributor
timestamp: March 29, 2016, 12:42:12 pm
content: Hope you don't mind if I sneak a question in here, the toms hardware storage forum didn't have any answers, and this is a similar topic.I'm wondering if any knows of any full sized PCI msata cards (With the built it holder for them, not some cable connection). I just sent off for a newer version of my server (hp proliant dl380 g6 instead of g4, nicely upgraded specs too, 2x 2.93ghz quad core xeons, and 60gb of ram, while the old server has 2x 3.2ghx dual core xeons and 6 gigs of ram), which can hold 8 sata/SAS hard drives, and I can add another carrier to make it 16, and for the use of network storage and general storage I'd like to use all of the hot swap bays strictly as storage, and have the OS on a separate one.I figure an msata controller card would be a neater way that tucking a full 2.5 inch drive somewhere in there, which I doubt there is room for lol.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:52:11 pm
content: Go with M.2 as mSATA is dead. If you want a card thesehttps://www.scan.co.uk/products/lycom-dt-125-1x-pcie-m2-ssd-plus-2x-sata-m2-ssd-pcie-30-x4-low-profile-host-adapter-card-for-windowsare good and have been used by many on the overclock.net forums.https://www.scan.co.uk/products/lycom-msata-to-sata-pcie-20-adapter-card-with-hybrid-driveif you really want mSATA but really unless you have an old mSATA drive M.2 is the way forward.

author: XOIIO
author_rank: Super Contributor
timestamp: March 29, 2016, 01:45:33 pm
content: Quote from: RGB255_0_0 on March 29, 2016, 12:52:11 pmYeah, unfortunately I don't think the pci riser in the server has pcie slots, it might, from what I saw in the options on the manual, but I'm not entirely sure yet so looking for a standard pci option. I really hope it does though, and thanks for the top on msata being dead.

author: Skimask
author_rank: Super Contributor
timestamp: March 29, 2016, 01:53:08 pm
content: Quote from: RGB255_0_0 on March 29, 2016, 12:36:09 pmThere is a buffer, but no power loss protection, hence why these are not classified as Enterprise grade. But these speeds are not burst write/reads. These are sequential read and writes.Ok, true, not burst speed in the sense that the drive is doing a bunch of look-ahead caching. More like, burst speeds in the sense that Windows/Linux/whatever grabs a few MB's of data, then has to figure out what to do with it.But, fear not. When the PC's get fast enough to handle all of this data going back and forth at seemingly ridiculous rates, developers will once again figure out a way to choke the system even harder and make it slow.Same shit...different day...

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 02:05:25 pm
content: Quote from: Skimask on March 29, 2016, 01:53:08 pmOk, true, not burst speed in the sense that the drive is doing a bunch of look-ahead caching. More like, burst speeds in the sense that Windows/Linux/whatever grabs a few MB's of data, then has to figure out what to do with it.But, fear not. When the PC's get fast enough to handle all of this data going back and forth at seemingly ridiculous rates, developers will once again figure out a way to choke the system even harder and make it slow.Same shit...different day...(SSD) Hard drives are still a bottleneck, especially when it comes to deep queue depths. A sequential read or write is quick; once you start stacking these commands they slow down greatly, as shown in the above benchmarks I did when I got my drive. One thing I will say about the drive is: boot time is just as quick as the 850 EVO I moved to another system. Bonus though of not having to route two more cables made up for that though with a much cleaner looking system.Quote from: XOIIO on March 29, 2016, 01:45:33 pmLooks to me there are 6 2nd generation PCI-E slots with optional PCI-X slots according tohttp://www.bargainhardware.co.uk/content/specifications/DL380G6_brochure.pdfMeaning you won't get the full benefit of a decent 4x PCI-E 3.0 SSD. 500MB/s per lane from gen 2.0 so 2GB/s for a 4-lane slot. Take some overhead away and I think you'll be looking at 1.8GB/s or thereabouts and I'd suspect no NVMe boot support without an OROM-based card like the Intel 750.

author: hayatepilot
author_rank: Frequent Contributor
timestamp: March 29, 2016, 02:10:27 pm
content: QuoteJup, cloud based stuff for example. The fastest storage means shit, if you have to squeeze it through the slow internet first.

author: Falcon69
author_rank: Super Contributor
timestamp: March 29, 2016, 05:07:56 pm
content: I bought the Samsung m.2 Ultra 951. My system boots up in about 20 seconds. It is 512GB. I also got 3x 4TB regular drives for storage.http://www.newegg.com/Product/Product.aspx?Item=9SIA2W032J1030&cm_re=samsung_951-_-20-147-426-_-ProductIt used to be that you could only get them with a LAPTOP purchase, i.e. Lenova. But I think Samsung finally allowed consumers to buy them separately. now they have the PRO version out now.From my understanding, these are the fastest on the market right now for a Solid State Drive.SLow internet isn't much of a problem with me hayatepilot. I'm getting 82mb/s here at home.

author: xyrtek
author_rank: Regular Contributor
timestamp: March 29, 2016, 06:13:27 pm
content: Not sure what choice you should make but I do have a system with a 951 and can probably run any test you may device to find your answer.I have the 512GB version and some 950Pro around. (maybe some old 940pros as well)anandtech has a lot of benchmarks (reviews) done to SSDs including the 951 (both AHCI and NVMe)http://www.anandtech.com/SearchResults?q=sm951

author: nctnico
author_rank: Super Contributor
timestamp: March 29, 2016, 07:44:14 pm
content: Quote from: NiHaoMike on March 29, 2016, 07:08:44 amI disable swap on Windows PCs with much less memory! Enabling swap makes Windows slow down to a crawl. Better run out of memory once in a while than waiting all day. Besides: swapping / virtual memory onto an SSD is asking for trouble because it will wear out the SSD real quick. I have a seperate hard drive in my PC for data which changes often.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 08:06:39 pm
content: Quote from: nctnico on March 29, 2016, 07:44:14 pmThis is an old wives' tale that needs to die.Google has released a study of 6 years' worth of data on wear and reliability. Age and manufacturing process (somewhat related) are bigger factors to SSD failure. My 830 Pro has undergone 5.65TB of written data and all I've done is let Windows perform a defrag on it (it's actually performing a TRIM command on SSDs, not defrag) and the life is still Good.There's no reason to worry about SSD wear as a typical (or even power user) as you will replace the drive before it's prone to failure.

author: Halcyon
author_rank: Unknown
timestamp: March 29, 2016, 09:33:57 pm
content: Quote from: RGB255_0_0 on March 29, 2016, 08:06:39 pmDid you even read the document you cited? It's not an old wives' tale at all. In their summary, they even explain:Both RBER and the number of uncorrectable errors grow with PE cycles, however the rate of growth is slower than commonly expected, following a linear rather than exponential rate, and there are no sudden spikes once a drive exceeds the vendor’s PE cycle limit, within the PE cycle ranges we observe in the field.It all comes down to how one uses the disk. You can't just assume flash memory will be tossed out and upgraded within a few years. I personally have some very old drives still in service. They don't develop TRIM and wear levelling for nothing. What they did say though was the manufacturers claimed program/erase cycle figure was conserative and rightfully so.6 years out of a drive is nothing unusual or uncommon. It's still a factor to be aware of.

author: RGB255_0_0
author_rank: Frequent Contributor
timestamp: March 29, 2016, 10:02:17 pm
content: Quote from: Halcyon on March 29, 2016, 09:33:57 pmThe actual statistics show that drive failure (bear in mind that these are in a datacentre environment) isslower than expected; age not usage affects reliability; SSDs fail at a lower rate than disks. I'll quote ZDNet: "The paper's second major conclusion, that age, not use, correlates with increasing error rates, means that over-provisioning for fear of flash wearout is not needed. None of the drives in the study came anywhere near their write limits, even the 3,000 writes specified for the MLC drives", and a major caveat to SSDs: "The SSD is less likely to fail during its normal life, but more likely to lose data."Irrespective of using a mechanical or solid state drive data backup is crucial, especially as the SSD ages because data corruption is more likely. Again, unless you can dispute the evidence of Google's data, what is safe to assume is that using an SSD as a scratch/page file does not noticeably wear an SSD. It's blatant scaremongering from the early days, and overprovisioning the SSD is not worth while: even if you were running databases there's no concern except you will want to change your drive a period sooner than a platter disk because of chip failure/defect.