Samsung SSD XP941 Review: The PCIe Era Is Here
by Kristian Vättö on May 15, 2014 12:00 PM ESTBoot Support: Mac? Yes. PC? Mostly No.
Booting from PCIe devices has always been rather quirksome because the BIOSes in motherboards are designed to boot from SATA devices, as they usually do. Most PCIe SSDs and SATA adapters include boot support by loading special drivers before the BIOS, which makes the drive visible in the boot screen. Without the drivers the drive won't show up in the BIOS but once you boot into the OS it will be accessible like any other drive. The problem is, you can't boot from the drive unless it shows up in the BIOS' boot screen.
Unfortunately, the XP941 doesn't seem to include the drivers necessary to enable booting. At least no driver loading screen shows up during boot, which suggests that the XP941 doesn't even have such drivers (ASUS is also telling us that this is the case). I'm thinking that the XP941 is designed for UEFI booting because from what I have heard, you don't need the drivers for UEFI boot but there is still some sort of a UEFI key needed to make the drive bootable. I did try the UEFI boot method on my ASUS Z87 Deluxe board but even though I was able to install the OS to the drive just fine, it wouldn't show up in the boot order.
The good news is that 9-series chipsets bring some ease to the situation. Back when the 8-series was introduced, there weren't many PCIe SSDs on the market but this year we will see PCIe entering the mainstream segment. That obviously forces the motherboard manufacturers to work on PCIe boot support and we can confirm that at least AsRock's Z97 Extreme6, which has a PCIe 2.0 x4 M.2 slot, supports booting from the XP941 out of the box. Whether other 9-series motherboards support booting from the XP941 remains to be seen. Most manufacturers, however, seem to be limiting the M.2 slot to just two PCIe 2.0 lanes, so you wouldn't want to use the XP941 in those boards anyway (unless the XP941 is used in a standard PCIe slot with an adapter). Anyway, we'll be sure to investigate the bootability of the XP941 in our motherboard reviews and work with the OEMs in order to bring better support for PCIe booting.
Update 5/20: ASUS just sent me an email that all their Z97 based motherboards will get a BIOS update that enables booting from the XP941. The BIOS is currently in beta testing and ASUS is expecting public release in about two weeks.
Macs, on the other hand, can boot from the XP941 just fine. I confirmed this using an early 2009 Mac Pro and the volume in the drive shows up in the boot option screen just like any other volume does. I have to admit that I don't know why exactly this is the case, but I'm guessing it's a fundamental difference between how the EFI in Macs and the BIOS/UEFI in PCs handle device recognition.
Under OS X, the XP941 shows up like any other SATA device. Since it utilizes the AHCI command set, OS X thinks it's a SATA device even though it's not. However, it's also listed under PCI cards but the page doesn't provide any meaningful info.
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BMNify - Friday, May 16, 2014 - link
rod, if you go ,as well as Everspin, look out for Crocus Technology Russian MRAM HW makers ARM licenced their IP , and Avalanche Technology tooRamCity - Monday, May 19, 2014 - link
Yes, I will be going to Computech. I'll add those vendors to my visit list and check out what they are up to if they have a booth.RamCity - Monday, May 19, 2014 - link
I mean Computex!Jay77 - Thursday, May 15, 2014 - link
I suppose I should read more than the first and last pages if I'm going to make comments.Babar Javied - Thursday, May 15, 2014 - link
There is a mistake/typo in "Performance Consistency & Trim Validation" under the "Trim Validation" section. Below the first graph in the said section, you have wrote "doesn't treat PCIe drives the same even if the utilize the same AHCI" when you ment to say "even if THEY utilize the same AHCI"Ryan Smith - Thursday, May 15, 2014 - link
Fixed. Thank you for pointing that out.BMNify - Thursday, May 15, 2014 - link
so basically you gimped the one and only raid 0 test by not doing it in windows or even better simply boot any linux iso/usb stick and formatted the ssd-xp941 WITH the samsung "F2FS" file system for maximum speed as that is written especially for ssdKristian Vättö - Saturday, May 17, 2014 - link
I did RAID the XP941s in Windows as well but the results were similar so I figured that there is no need to report the results separately.rocky12345 - Thursday, May 15, 2014 - link
I like that there are extra speed speed in these new devices but it seems everyone is so stuck on more speed more speed..lol I am sorry but when a standard SSD can boot a windows 7 in about 6 seconds when are people going to be happy. My Asus laptop has a SSD in it & boots in about 6 to 7 seconds & things like firefox open even before my finger un-clicks the mouse button to open firefox. now everyone is saying standard SSD is to slow..lol to funny. What I would rather like to see is bigger SSD drives at a better price. We already have good speed but the big drives still cost to much for most people when they can make a 1TB SSD at about the same or just slightly more than a standard hard drive then maybe they should be more worried about all these new extreme speed drives but if they make standard SSD drives go the way of the doo doo bird then we are never going to see low priced SSD anything because they will always be treating anything SSD related as new tech just a thought.BMNify - Thursday, May 15, 2014 - link
"but it seems everyone is so stuck on more speed more speed..lol I am sorry but when a standard SSD can boot a windows 7 in about 6 seconds when are people going to be happy..."well obviously speed is not for you, but how do you expect current non volatile ram to lower in price if they don't bring out newer kit to replace it at today's higher price points !
im not sure you understand the driving forces here as regards people wish for faster data access, we really need/WANT a so called "universal non volatile ram [such as those Everspin ST-MRAM DDR3 DIMMs referenced ]" sooner than later at equivalent ddr3 2400,wideIO2,HMC speeds and configurations so we can start to take better advantage of the higher data throughput and data manipulation these bring to the table, its not good enough to x264 encode UHD content in real time right now, then and only then will we start to consider we are starting to get close to enough general speeds, ALIMO.... YMCV