Six-Drive SATA III SSD Round-Up Shows Big Gains

MojoKid writes "Solid state drives have gone from essentially non-existent on the desktop to the preferred storage medium of enthusiasts and workstation professionals in less than three years. Three of the drives featured in this six-drive SATA III SSD round-up consistently offered 'best-of-class' performance throughout testing, with speeds in excess of 500MB/s for read and write throughput. OCZ's Vertex 3 Max IOPS, Corsair's Force GT, and the Patriot Wildfire all feature the same SandForce SF-2281 controller and synchronous NAND flash memory. These drives offered the highest transfer rates in the majority of tests, though performance does drop off as the data gets more incompressible."

Comments

However, something important to keep in mind

[Sycraft-fu]

At this point, all SSDs are basically "fast enough" for desktop usage. You notice a major difference between an SSD and a HDD. You don't notice much, if any, difference between a lower and higher end SSD on the desktop.

The same is not true on servers, of course, the heavier random load makes IOPs a big deal in various servers (databases particularly).

While I'm certainly not saying don't get one, I'm saying don't dump your SATA II SSD if you have one for these, and don't pass up a SATA II SSD if it is on sale.

Re:However, something important to keep in mind

[Solandri]

At this point, all SSDs are basically "fast enough" for desktop usage. You notice a major difference between an SSD and a HDD. You don't notice much, if any, difference between a lower and higher end SSD on the desktop.

A large part of the reason SSDs are faster than HDDs is their low latency (has a big impact on small file read/writes). However there's another big reason you don't notice much difference between lower and higher end SSDs: We're using the wrong metric.

SSDs and HDDs benchmarks are almost universally given in MB/s. The problem is, people don't perceive speed in MB. They perceive it in seconds. The computing tasks you need to get done are almost never "I can wait 1 second. How much data can my computer crunch?" They're of the type "I need to crunch 1 GB of data. How many seconds will that take?" So the correct metric we should be using is s/MB.

But it's the same number! Why should this make a difference? Because when you invert a metric, the big numbers become small numbers, and the small numbers become big numbers. e.g. Say you have a HDD which can read 100 MB/s, a cheap SSD which can read 200 MB/s, and an expensive SSD which can read 500 MB/s. So in 1 second, the HDD reads 100 MB, the cSSD 200 MB, and eSSD 500 MB. Expressed in MB/s you gain 100 MB/s switching from HDD->cSSD, and a whopping 300 MB/s switching from cSSD->eSSD. Switching from cSSD->eSSD gives you 3x the benefit of switching from HDD->cSSD! So the extra money for the expensive SSD is definitely worth it! Right?

Hold on. Invert to s/MB and say you need to read 1 GB. The HDD takes 10 sec, the cSSD 4 sec, and the eSSD 2 sec. Switching from HDD->cSSD saves you 6 seconds. Switching from cSSD->eSSD only saves you 2 sec. So in terms of time you spend waiting, the HDD->cSSD switch saves you 3x as much time as the cSSD->eSSD switch. The vast majority of your time saved can actually be obtained from the switch to the cheaper SSD. The next step switching to the expensive SSD only gives you a marginal improvement. (Even if you insist on using relative measures of time, the cheap SSD still wins. 10 sec to 4 sec is a 60% reduction in time. 4 sec to 2 sec is only a 50% reduction in time.)

Anandtech basically stated as much in a recent SSD review. They admitted that in real world use (i.e. benchmarks measured in seconds), there really isn't much difference between the different SSDs. But reviews with benchmarks showing all products having nearly the same result doesn't get people coming back to read more reviews. So to hype people up, reviewers invert the scale and measure in MB/s to exaggerate small differences. Differences which for the vast majority of people are so small as to be nearly meaningless in their real-world computer use.

The same thing crops up with fuel mileage in cars. Fuel consumption is actually gallons per mile. But because the U.S. measures it in miles per gallon, it exaggerates the benefit of high mileage vehicles. If you ask a dozen people which saves more gas, switching from a 14 MPG SUV to a 25 MPG sedan, or switching from a 25 MPG sedan to a 50 MPG hybrid, I will bet nearly all of them will say switching to the hybrid saves more gas. After all, 50-25 = 25 MPG improvement, while 25-14 = only a 11 MPG improvement. But if you drive 100 miles:

14 MPG SUV = 7.1 gallons used
25 MPG sedan = 4 gallons used
50 MPG hybrid = 2 gallons used

Surprise. The 11 MPG improvement switching from the SUV to sedan saves you 3.1 gallons per 100 miles driven, while the 25 MPG improvement switching from sedan to hybrid only saves you 2 gallons. The metric we should be using is GPM, not MPG. The rest of the world measures fuel consumption in liters per 100 km for this reason. (A consequence of this is that if we as a nation wish to lower our fuel consumpt

Re:However, something important to keep in mind

[Rennt]

The 11 MPG improvement switching from the SUV to sedan saves you 3.1 gallons per 100 miles driven, while the 25 MPG improvement switching from sedan to hybrid only saves you 2 gallons.

Classic mistake. You can' t make a comparison without a baseline.

So lets use GPM.
4 / 7.1 = 0.56
2 / 7.1 = 0.28

OK, what about MPG?
25 / 50 = 0.5
14 / 50 = 0.28

Doesn't make a lick of difference if you use X/y or Y/x. Switching to a hybrid will save your nearly twice as much fuel as switching to a sedan would. The numbers don't lie.

Re:However, something important to keep in mind

[GooberToo]

You notice a major difference between an SSD and a HDD.

I completely agreed. Most report total drive failure in 6-18 months with SSD drives with absolutely no warning of impending catastrophic failure. So ask yourself, are you ready for complete data loss every 6-18 month, while paying an extreme premium for the privileged? Most recommend NOT using these as your primary device, but rather use a smart caching device, which uses these devices as an accelerator while still using the HDD as your primary, dramatically more reliable, long term storage medium. Of course, in either case, a sane, complimentary backup strategy should employed.

Why no testing with pci-e SDD cards next to the

[Joe_Dragon]

Why no testing with pci-e SDD cards next to the Sata-3 disks?

also should test with a HIGH END SAS / SATA raid card.

Re:Why no testing with pci-e SDD cards next to the

[ub3r n3u7r4l1st]

Right now TRIM command don't pass through RAID chips. So unless these SSD comes with robust garbage collection algorithm I wouldn't put those in RAID.

Re:Why no testing with pci-e SDD cards next to the

[billcopc]

TRIM is nowhere near as big an issue as people think. GC works fine on both Indilinx and Sandforce units. Realistically, once you start talking about RAID, the modest and highly situational performance gains from TRIM become irrelevant. Even with TRIM support, the block erase still happens in the background, so there is some delay before write performance is restored. If you're in a heavy rewrite scenario, you gain nothing as the drive doesn't idle long enough to handle those deferred erases anyway. And if you're not a heavy rewriter, the GC will take care of it sooner or later. It's all so moot.

My Revodrive X2 hits 650mb/sec with ease. My new Velodrive goes up to about 1000mb/sec, despite having a gazillion apps and games installed and my careless use of my "desktop" folder as temp space. The bottleneck is the shitty Silicon Image RAID chip, not the lack of TRIM. A very interesting product on the radar is the new Angelbird Wings, another PCI-E SSD with some cool features not found in the other brands, like mounting ISOs as virtual CDs at boot time, and a built-in Linux/XFCE distro for management/partitioning. They're claiming 900mb to 1000mb/sec speeds on the 4-channel model.

Still think TRIM is the deal-breaker ?

SATAIII is great, but unstable

[Anonymous Coward]

Before getting excited and rushing off to buy a SATAIII SSD, bear in mind that there are currently some serious stability issues in some of the drives. I recently bought a Corsair Force 3 120GB, only to discover that many, many (as in most) customers are experiencing problems with system hangs and BSODs. I've been lucky enough to only have the drive lock up once a day after a full day of use, but plenty of folks only last about an hour. The old drives were recalled, but even the replacements are having the same problems. This a big support thread at http://forum.corsair.com/forums/showthread.php?t=96333, and plenty more just like it in the same forum.

Corsair seems to think this is an issue with the SandForce controllers, which is reasonable considering other big names (OCZ, for instance) are having the same issues with some of their new drives. Just be sure to do your research first.

Re:they still need to be a lot bigger now 500GB an

[fuzzyfuzzyfungus]

While, of course, I'd like all that and a pony, I recognize that ours is not exactly a perfect world. Big SSDs are expensive and big HDDs are (comparatively) slow.

What would be nice, though, and arguably rather more reasonable(it's only a matter of software, and across millions of users the unit cost should be approximately fuck all), would be seeing the tech for transparently dividing workloads across two or more disks with heterogenous characteristics descend from its present position in expensive SANs and comparatively esoteric server FSes.

Sure, the manual "OS+applications on SSD, porn and torrents on HDD" tactic works more or less alright; but having humans wasting their time doing a (lousy) attempt at a machine's job seems like such a pity. Handling the messy details of physical storage location, in order to achieve best apparent performance with lowest burden on the operator, is exactly the sort of abstraction that our computers should be handling for us.