AMD and Seagate discuss the new 6Gbps SATA Standard
by Gary Key on March 9, 2009 12:00 AM EST- Posted in
- Gary's First Looks
AMD and Seagate are teaming up today in New Orleans to demonstrate the next-generation Serial ATA specification. The new specification, SATA 6Gbps, will offer twice the disk-to-host bandwidth of the existing 3Gbps Serial ATA standard. Besides the improvement in bandwidth, SATA 6Gbps offers full backwards compatibility with the earlier 3Gbps and 1.5Gbps standards, including the same cable and connector specifications.
AMD and Seagate have worked extensively on fine-tuning data streaming characteristics and users should expect to see significant improvements in this area over current 3Gbps NCQ implementations with the new drives. In addition, the new power management scheme allows the platform to instantaneously power on and off the 6Gbps SATA interface, unlike the always-on power state in current SATA systems.
Current Serial ATA hard drives on the market have average transfer rates that peak around 120MB/s, but read transfers out of the drive buffer (cache) are already hitting 288MB/s. Current caches are at 32MB with a move to 64MB shortly that will place further pressure on the current standard. In fact, the drive (modified 7200.12 design) that Seagate will demonstrate today has read transfers out of the driver buffer hitting 589MB/s.
However, the big winner initially with the new 6Gbps standard will be flash-based drives. We already have SSD drives like the Intel X25-E hitting sustained read and write rates over 200MB/s with new drive designs coming late this year that will probably saturate the current 3Gbps interface. The first customers that Seagate and AMD plan to address with this new technology are enthusiasts, low-end server markets, and users who stream high definition videos or do intensive graphics multimedia work.
Seagate and AMD were adamant that today’s technology demonstration is not an official product launch. That will come later this year when AMD formally announces their next generation chipset featuring full support for the 6Gbps standard. Both companies told us that 6Gbps SATA products might arrive before the end of 2009 but nothing is officially in the pipeline as of now.
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9nails - Tuesday, March 10, 2009 - link
Wait a second... Which hard drives are breaking 250 MB/s? You're talking transfer rates right? That seems super quick, even my favorite little VelociRaptor's don't touch 130 MB/s read transfer rate.blyndy - Tuesday, March 10, 2009 - link
Many people are waiting for the release of power over SATA. Where is it?piroroadkill - Tuesday, March 10, 2009 - link
Faster SSDs that can easily saturate it? DRAM based SSDs? I don't see a reason why we shouldn't make it faster.UNHchabo - Monday, March 9, 2009 - link
The big reason is so that we can have more headroom.My WD 640 can't even max out my SATA 1.5Gbps link except maybe on cached workloads, but that doesn't mean I wouldn't like a 6Gbps link.
v413 - Monday, March 9, 2009 - link
Yes, it is needed. The reason why is mainly because of SSDs. And SSDs will soon easily eat up even the provided bandwidth of SATA3. Micron for example are currently developing an SSD with 1GB/s throughput (800MB/sec demonstrated) that will use PCI express.mariush - Thursday, March 12, 2009 - link
Actually, they got up to 2100+ MB/s using 10 Samsung SSD drives and 800 MB/s using 24 in a RAID (hardware controller was simply not capable of using all 24 at a time and keep the throughput)Here's the Youtube video:
http://www.youtube.com/watch?v=96dWOEa4Djs">http://www.youtube.com/watch?v=96dWOEa4Djs
Veerappan - Monday, March 9, 2009 - link
Due to the way that SATA traffic is encoded, 2 bits of every 10 is lost, and not usable for data transfer (8B/10B encoding). Because of this, the max transfer rate of SATA is 300MB/s, not 375MB/s. As mentioned, some drives are hitting ~290MB/s from cached reads, which is essentially saturating the bus (300MB/s is the theoretical max, not necessarily the usable max).I'd say for people who are in this situation could use 6Gb/s SATA right now (or should switch to a different underlying technology).
JarredWalton - Monday, March 9, 2009 - link
I wouldn't be surprised if there's also the old MB vs. MiB issue cropping up. Most software applications still measure megabytes as 1024^2, but hard drives measure it as 1000000. So 288MiB/s would in fact be 301,989,888 bytes per second, which fully saturates a 3Gbps SATA link. Likewise, 589MiB/s would be 617,611,264 bytes per second, so the buffer of a drive can already saturate the 6Gbps link. Of course, as someone else points out below, reads from the buffer are really a marketing gimmick. SSDs on the other had will likely top out on 3Gbps in the next year, making 6Gbps necessary for further speed improvements.yyrkoon - Tuesday, March 10, 2009 - link
Uh . . . no . . . bandwidth, not storage.Also, Veerappan, you do know what maximum theoretical means do you not ? 2b encoded is still information sent. But why say "8b/10b encoded", when you can say 20% communications/controller overhead.
Spivonious, because a SATA channel is not limited to a single drive. Read about SATA port multipliers sometime.
quiksilvr - Monday, March 9, 2009 - link
Why is there a Megabit and a Megabyte? Cant we just choose byte and be done with it?