OCZ Vector (256GB) Review
by Anand Lal Shimpi on November 27, 2012 9:10 PM ESTTRIM Functionality
Over time SSDs can get into a fairly fragmented state, with pages distributed randomly all over the LBA range. TRIM and the naturally sequential nature of much client IO can help clean this up by forcing blocks to be recycled and as a result become less fragmented. Leaving as much free space as possible on your drive helps keep performance high (20% is a good number to shoot for), but it's always good to see how bad things can get before the GC/TRIM routines have a chance to operate. As always I filled all user addressible LBAs with data, wrote enough random data to the drive to fill the spare area and then some, then ran a single HD Tach pass to visualize how slow things got:
As we showed in our enterprise results, Vector's steady state 4KB random write performance is around 33MB/s. The worst case sequential performance here is around 50MB/s, which is in line with what you'd expect. Sequential writes do improve performance, but as with most SSDs you're best operating the Vector with a bit of spare area left on the drive (in addition to what's already set aside by firmware).
TRIM and another sequential pass restore performance to normal, but it also triggers the Vector's performance mode penalty:
At 50% capacity there's an internal reorganization routine that's triggered on Vector, similar to what happens on the Vertex 4. During this time, all performance is impacted, which is why you see a sharp drop in performance just beore the 135GB mark. The re-org routine only takes a few minutes. I went back and measured sequential write performance after this test and came back with 380MB/s in Iometer. In other words, don't be startled by the graph above - it's expected behavior, it just looks bad as the drive doesn't get a chance to run its background operations in peace.
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Anand Lal Shimpi - Wednesday, November 28, 2012 - link
The write amount does actually scale with capacity, OCZ just tried to simplify things with how they presented the data here. In actuality, even the smallest capacity Vector should be good for more than 20GB of host writes per day x 5 years.Take care,
Anand
jwilliams4200 - Wednesday, November 28, 2012 - link
Wait, what? I thought OCZ claimed the warranty was the same for all capacities, 5 years of 36TB, whichever comes first.Are you saying that the 36TB number is only for the 128GB Vector, and the other two have double and quadruple that amount allowed before the warranty runs out?
Kristian Vättö - Wednesday, November 28, 2012 - link
OCZ only says 20GB of writes a day for 5 years in the Vector datasheet, no capacity differentiation:http://www.ocztechnology.com/res/manuals/OCZ_Vecto...
JellyRoll - Wednesday, November 28, 2012 - link
These endurance tests that they use to generate the predicted life of the SSD are with 100% fill and full span random writes. This prevents the SSD from doing many of the internal tasks as efficiently that reduce write amplification. You would need to be doing full span random writes to see these types of endurance numbers.Free capacity on the drive, and different types of data other than 4K random will result in much higher endurance.
These numbers are intentionally worst case scenarios.
A5 - Wednesday, November 28, 2012 - link
If your usage case is saturating a Gigabit connection 24/7, you need to be buying SLC Enterprise drives (and get a better network connection :P).36TB doesn't sound like much if you're making up crazy scenarios, but that is probably near a decade of use for a normal power-user. Another way to put it is that you'd have to re-install a 12GB game 3,000 times to get that number..
seapeople - Sunday, December 2, 2012 - link
But if you reinstall a 12GB game four times per day, and eight times on a Saturday, then your drive could be worn out after just three months!It's a reasonable use case for someone who only wants to spring for the budget 40GB SSD, but still wants to oscillate between playing four large games on a daily basis.
jwilliams4200 - Monday, December 3, 2012 - link
Your math is off. That is only 713GB.jwilliams4200 - Monday, December 3, 2012 - link
Oops, my math is off, too. But yours is still off.3 months is 13 weeks, so 13 Saturdays and 78 non-Saturdays.
12*(4*78 + 8*13) = 4992GB
So you have to do that 7.2 more times to get to 36TB, which is about 1.8 years.
jeff3206 - Wednesday, November 28, 2012 - link
Vertex, Octane, Agility, Synapse, Revodrive, Z-Drive, Velodrive and now Vector, plus an array of generation numbers and suffixes. Could OCZ's flash product naming system be any more complicated?Numerical product names may not be sexy, but they sure are easy to understand.
wpcoe - Wednesday, November 28, 2012 - link
Chart on first page of review shows Sequential Write speed for 128GB model as 530MB/s, when the OCZ site (http://www.ocztechnology.com/vector-series-sata-ii... shows it as 400MB/s.