OWC has released their first PCIe SSD, the Mercury Accelsior. OWC has used SandForce controllers throughout its history in the SSD world and the Accelsior is no exception. It is equipped with two SandForce SF-228X controllers, which are the same controllers that can be found inside OWC's other SATA 6Gb/s SSDs. 

The actual design is pretty interesting. OWC has opted to build the SSD out of two blades, each with their own controller and NAND running. The blades run in RAID 0 by default but they can also be configured in RAID 1 mode. Oftentimes everything is intergrated on one PCB but OWC's approach is different, and there is actually a big advantage todoing things this way. Using blades allows the capacity to be upgraded without buying a totally new card. OWC does not sell the blades separately yet, but manufacturing new blades should be somwhat cheaper than manufacturing the whole PCB, so down the road this could result in a lower total upgrade price.

OWC Mercury Accelsior Specifications
Capacity 120GB 240GB 480GB 960GB
Controller Dual SandForce SF-2281 Dual SandForce SF-2282
NAND 24nm Toshiba Toggle-Mode MLC NAND
Interface PCI Express 2.0 x2
Form Factor Low Profile PCI Express
Sequential Read 758MB/s 762MB/s 780MB/s 756MB/s
Sequential Write 743MB/s 763MB/s 763MB/s 673MB/s
4K Random Read Up to 100K IOPS
4K Random Write Up to 100K IOPS
Price $360 $530 $930 $2096
Warranty 3 years

OWC's Mercury Accelsior is actually a very competitive drive. A quick look at NewEgg shows that OCZ's RevoDrive 3 is not significantly cheaper--in fact, it's more expensive at 480GB and above. OCZ does claim better performance but it's good to keep in mind these figures meant for advertising.

OWC is primarily an Apple focused company and here is the big deal: Mercury Accelsior supports booting under OS X. There are plenty of PCIe SSDs out there but OWC's is the first one that supports booting into OS X. No drivers are needed in OS X or Windows either--the drive is plug and play. Booting into Windows has not been a problem but it's understandable that a Mac user has little need for a PCIe SSD that only boots into Windows. Unfortunately Mac Pro is the only Mac that has empty PCIe slots and Apple has not shown much love for the Mac Pro lately.

Availability for the Mercury Accelsior line starts now, though only the linked prices above are currently showing up online.

Source: OWC

Comments Locked


View All Comments

  • quanstro - Thursday, April 19, 2012 - link

    wiki disagrees: http://en.wikipedia.org/wiki/PCI_Express#Architect...
    2x is not defined.

    since the device can only connect at pcie 2.0 x1, it will be limited to 500mb/s.
    the 780mb/s numbers quoted are not plausible given this configuration.
  • Penti - Thursday, April 19, 2012 - link

    Your not reading or understanding anything in the comments section or at the wiki, look at the Marvell link or simply count the pins and you will see that it is two lanes and that PCIe can use any number of lanes and that the hardware can negotiate any number of lanes that it supports, you can run a graphic card at x2 too for that matter. Slots and electrical are two different things here. The controller are designed to work with up to two lanes.

    "A connection between any two PCIe devices is known as a link, and is built up from a collection of one or more lanes. All devices must minimally support single-lane (×1) link. Devices may optionally support wider links composed of 2, 4, 8, 12, 16, or 32 lanes. This allows for very good compatibility in two ways:"

    There is no problem fitting a smaller card in a bigger slot, it's designed that way.

    They would basically need a 8-port SAS-controller for x4 PCI-e support. At least as far as Marvell is concerned.
  • -=Hulk=- - Thursday, April 19, 2012 - link

    1. No PCIe x2 is not allowed. Look at recent news, Intel wanted a 2x PCIe as standard but the consortium on charge of PCIe doesn't agree with the idea. If you want tu use 2 PCIe lane with this Marvell controller you have to use a 4x PCIe controller at least.
    You can't aggregate 2 x1 lanes. It works only if the client chip has a internal or external PCIe switch (like those from PLX)

    2. Look at the picture! It's a x1 connector on the card. How do you want the Marvell controller to use 2 PCIe lanes???
    This SSD card won't exceed ~480-500MB/s.
  • -=Hulk=- - Thursday, April 19, 2012 - link

    Sorry it's not a 1x on the picture :D. But it's not standard.
  • daytrippr - Thursday, April 19, 2012 - link

    While PCIe does not provide for a 2x physical slot, it unambiguously supports a 2x electrical interface. Plug a x2 card into a x4 slot and you'll get the much higher performance numbers you seem to want to ignore...
  • Penti - Friday, April 20, 2012 - link

    Slot != Card that was what my post also said, we all know that it's x1, x4, x8, x16 and x32 as far as slots go. Or mechanical interface. When it's internal on the motherboard it doesn't matter and saves lanes using only as many as you need. Using a >x4 slots leaves two or more lanes unused. There are some motherboards with electrical x2 slots though. No Mac of course. Here we simply have a card with a SATA-controller designed to be used with two lanes.
  • AnnihilatorX - Friday, April 20, 2012 - link

    But did Intel mean a dedicated x2 physical slot or just a x2 electrical interface?
  • extide - Wednesday, April 25, 2012 - link

    Yes. PCIe x2 IS allowed. That card IS a 2x physical AND electrical card. PERIOD.
  • joevt - Sunday, May 27, 2012 - link

    A problem with x2 is that PCIe chips aren't required to negotiate 2 lanes. For example, the ESB2 south bridge (PCIe 1.0) in the 2006, 2007, and 2008 Mac Pro's and other old PC's can only negotiate 1, 4, or 8 lanes. The Accelsior in such a slot will only use a link width of 1 lane for 195 MB/s read/writes. Even with a 2 lane link width (as provided by the 5000 series north bridge chip in the Mac Pro 2006, 2007), the Accelsior will only do 380 MB/s in a PCIe 1.0 slot.

    I wonder if any PCIe 2.0 chips have the same link width limitation. The 5400 north bridge chip in the Mac Pro 2008 handles x2 fine.
  • Gary Byatt - Thursday, April 19, 2012 - link

    I have been using the OCZ Revodrive 3 x2 240GB since November in a self-build with a i7 2700K CPU that clocks up to 3.9GHz on load and 8GB of 1833MHz RAM.

    I get a windows performance index of 7.9 on the OCZ as my boot drive. I tested it after a few months of real world usage and reported my findings here: http://www.linkedin.com/groups/240GB-OCZ-Revodrive...

    In short I got a best write of 1129.555 MB/s and a best read of 1520.693 MB/s. The best write speed is a little short of the advertised 1225 MB/s but it is in use as the boot device on machine in real use, not sitting idle waiting for test data in a lab. The best read speed is actually slightly better than the advertised 1500MB/s, so “figures meant for advertising” or not it is a lot better in real use than the OWC claim.

    I expect to see storage from OCZ in the not too far distant future that saturates 4 lanes of PCIe v2 (2GB/s).

Log in

Don't have an account? Sign up now