Seagate has finally started shipping their new Barracuda XT 2TB drives that feature the new 6Gb/s SATA interface based on SATA Revision 3.x specifications. We had an early preview of the drive a few weeks ago and finally received a production level item for review. Just as important, we now have retail motherboards from Asus and Gigabyte featuring 6Gb/s capabilities. Well at least the Marvell 88SE9123 chipset included on both motherboards is theoretically capable of 6Gb/s operation.

Asus and Gigabyte took a different approach to implementing the Marvell 9123 chipset on their motherboards. Asus’s top of the line P7P55D Premium (a very good board by the way, full review coming shortly) features a PEX PLX8613 PCIe bridge chip that will convert four of the P55’s PCIe x1 lanes (250MB/s each) into two 500MB/s lanes. While still short of the maximum theoretical 600MB/s transfer speed of the SATA 6G specifications, it will provide more than enough burst bandwidth for the first generation 6G hard drives. The benefit is that the 6G capability is always on without affecting the other capabilities of the board and the same PLX chipset will be utilized for the upcoming USB 3.0 (NEC chipset) option on their upper-end boards.

Gigabyte’s implementation will be utilizing an x8 PCIe 2.0 from the Lynnfield processor that will obviously provide more than enough bandwidth but the drawback is that CF/SLI capabilities will be disabled as only a single x8 PCIe 2.0 lane will be available to the GPU. The benefit in this approach is that the SATA 6G switch is disabled/enabled in the BIOS by the user based upon need. Since an additional hardware chipset like Asus is utilizing is not required, it should result in a slightly lower board cost. Gigabyte informed us this week that all P55A-xxx boards will feature both SATA 6G and USB 3.0 capabilities. We will compare the performance of Gigabyte’s solution against Asus’ implementation shortly.

For today’s preview we are utilizing the Asus P7P55D Premium motherboard, 8GB of GSkill’s DDR3-1600 Ripjaw memory, Asus HD5870 video card, Corsair 750HX power supply, Windows 7 x64 RTM, Western Digital Caviar Black 2TB HD, WD VelociRaptor 300GB, Intel X25-M G2 160GB SSD, and Seagate’s Barracuda XT 2TB HD. We will have a full review of both hard drives shortly with additional performance results along with temperature and noise tests.

We are utilizing the Intel 160GB SSD for our OS drive and comparing the Seagate XT drive to its closest competitor, the WD Caviar Black, on both the Intel P55 and Marvell 9123 controllers. The P55 is limited to SATA 3Gb/s operational mode when running either drive, while the Marvell controller will be operated in SATA 6Gb/s mode with the Seagate drive and in fallback 3Gb/s mode with the WD drive. We are utilizing Marvell’s latest 1027 driver and Intel’s driver set in AHCI mode.

HD Tune 3.50 Results -

See something strange, the read burst rate of 2766MB/s and write burst of 2705MB/s are incredible for single drive performance but like most synthetic test results, they are not a true indication of actual platform performance. The reason for these “outstanding” results is that Marvell’s latest driver allocates (dynamically) a portion of system memory for transfer cache operations. Intel’s own Matrix Storage Manager and JMicron’s latest driver set also utilize a similar approach. In fact, Windows 7 implements a similar type of caching at the kernel level that makes these driver optimizations redundant in some ways.

Marvell is using aggressive algorithms in this particular driver to read and write as much possible data out of the RAM cache as possible before relying on transfers via the hard drive’s own internal cache or reading/writing from the platter or NAND. In earlier driver sets from Marvell, they requested that Window’s write-cache buffer flushing option be disabled in order to gain the maximum benefit from the 9128 controller. From all indications, the 1027 driver automatically disables this function as our performance results were the same with it disabled or enabled.

While performance was generally up to 10% better with this driver compared to the earlier 1018/1025 driver sets, we have a problem with the write-cache buffer flush being disabled automatically. There is a potential for data loss or even file table corruption if the buffers are not flushed and written properly if power is lost or there is another problem with the system. Of course that potential problem even exists with the out of box drivers and with write-caching enabled.

Our concern is that the Marvell driver might not recognize file table priorities in the same manner that the kernel does and those journal entries will be placed into the same general cache queue with other mundane requests. That could increase the likelihood of data or table corruptions above the normal risk posed with write caching. We are still waiting on additional information about the driver design and will update our findings in the final review.

AnandTech Storage Bench


View All Comments

  • Zak - Thursday, October 29, 2009 - link

    Yeah, with port multiplier enclosures data from several drives is transferred over single SATA link. I had port multiplier 4-drive enclosures and with 4 hard drives in RAID0 I was easily maxing out the SATA3Gbps bandwidth.

  • chrnochime - Thursday, October 29, 2009 - link

    300 USD for the Premium Asus board as compared to ~170 for a P7P55D pro version just to have 6GB Sata and USB 3.0? That's a steep price to pay for just these two features. Reply
  • chrnochime - Thursday, October 29, 2009 - link

    and it's 6Gb not GB whoops. Reply
  • DLeRium - Thursday, October 29, 2009 - link

    I hate seeing AT falling into the realm of previews. We seem to get more and more of these. Each preview promises followup reviews, but I see less and less follow up reviews or flat out full reviews. Remember when AT reviewed the WD 640gb Blue and the 7200.8s, 7200.10s, all that? Those were nice solid reviews. Now we get previews. Core i7 preview into OCing. No OCing guide today. The only motherboard roundup we got was the 3 or 4 motherboards we had at the i7 launch, while Toms spent 3 or 4 articles doing separate groups of roundups (enthusiasts, midrange, budget X58). I hate THG, and I always respected AT's opinion more, but when we're getting more and more half-assed reviews that are barely finished that DEPEND on follow-ups that aren't always done, then I have a problem.

    I'd rather see a solid review and be done with it. I'm glad we got a WD 2TB Black, but are you guys going to review that? AT is definitely leading the charge into the SSD world, but as we're doing it, we're forgetting a lot of nice new drives like the WD 2TB Black that I feel deserves a full review. Same with the new Seagate 7200.12s.
  • Zool - Thursday, October 29, 2009 - link

    I think that people dont buy 2TB drives for speed. If u hawe TB-s data that u need to store its the only choice. With those read speeds u could watch fine a 500 Mbit video stream. Actualy with 64bit around for years you could have a 32GB system with for example 24GB ram disk. And ram disk working with intesive read write workload is like 100 times faster than the best ssd. But its actualy rare to have 4+ GB memory still. I think that the storage will be in future in levels like CPU cache. L1 storage smaller for used data and L2 for storage of large data. Or even a ram level (actualy cpu memmory should be divided in levels long ago, buying 32GB of very fast memmory is overkill.U could hawe 2GB realy fast memory and a very cheap 32GB memory which is still much faster than anything else)
    Everyone who can use brain already know that 6Gb/s sata is just a marketing buzz unless u use a giant raid.
  • Zak - Thursday, October 29, 2009 - link

    Actually, as I went up to 1TB and larger drives I started wishing for more speed too. I use 1.5TB and 2TB disks as backups and mirrors and full backups of terabytes of files take a long time:) Reply
  • Zool - Friday, October 30, 2009 - link

    You need to be patient. It wont change any time soon. Even with ssd speeds backup TB-s of data takes hours.
    Hint: Dont backup that often :)
    Maybe there are some programs that monitor only files that were changed and only backup those, not the whole drive. If u want backup that often.
  • yyrkoon - Thursday, October 29, 2009 - link

    Like another user has already mentioned, there is port multiplier technology, which is about the only thing that can use this additional bandwidth _right_now_ . Even then, the drives must be in some form of RAID, and if for performance, you're still going to see access time "doubling".

    The point here would be I think if people cared that much about performance, they would opt for at minimum an inexpensive SSD that performs decent for a SSD, and completely destroys any mechanical drive. This is not to say that I think your tests are null and void. This *IS* to say that I think that people are going to be more worried about reliability concerning these drives, not so much about performance as long as the performance is close to something reasonable for the technology. I think both drives in this test have demonstrated this level of performance.

    Now if you guys really want to impress us mere mortals with numbers, let us see you guys at Anandtech put two iSCSI targets with 32GB of ramdisk each out to a single initiator as a RAID 0 array. Then watch how the drive visible on the initiator smokes all of your tests ;)

    Wait until Starwind implements "true" RAID 0 over multiple links the correct way, and it will be even "funner".
  • Griswold - Thursday, October 29, 2009 - link

    "Like another user has already mentioned, there is port multiplier technology, which is about the only thing that can use this additional bandwidth _right_now_ . Even then, the drives must be in some form of RAID, and if for performance, you're still going to see access time "doubling"."

    No, they dont have to be in any form of RAID. With a PM you can hook them up as individual drives if you want. My point was and still is that with a PM you can saturate a 6Gb/s port that way - but that would be sort of pointless unless you need to hook up more drives than you can attach to your motherboard by using the one-drive-per-port scheme. But if you do need this, this Sata 6Gb/s thing starts to make sense even with spindle drives.
  • yyrkoon - Thursday, October 29, 2009 - link

    If you do not RAID them on a port multiplier, you gain no performance. Read the white papers on SATAIO if you doubt me. As I have known about this technology for more than 5 years now.

    You can run singles on a port multiplier if you wish, but only one drive will be able to communicate with the system at a time. This is not a bad thing really, because PM will allow you technically up to 15 more drives per port I believe( 16 devices total like SCSI ), but the highest number of drives allowed on current hardware available is only 5 drives per port.

    Another downside to port multipliers is that is is all handled in software.Either you use the software provided by the manufacturer, or it is handled in hardware like fake RAID. In the end, it is all software, whether embedded, or not. Also, you require specific chipsets in order for this technology to work at all. In he end, it is not a terrible idea, but SAS puts it to shame. The only downside to SAS is that you require an SAS expander per 8 drives. Since expanders are not cheap, the cost mounts up pretty quickly. Still, it is by far the superior technology.

Log in

Don't have an account? Sign up now