When Does The 128 GB Vertex 4 Slow Down?
Our testing indicates that the Vertex 4 128 GB drive's write performance is negatively impacted if sustained write activity extends beyond 50% of its free capacity. When this occurs, sequential and 4 KB random writes above a queue depth of one take a notable hit. When sustained writes extend to less than 50% of available capacity, however, performance is not affected. Therefore, the likelihood that you'd see the Vertex 4's potential suffer depends on the amount of free space you leave and the size of file transfers that occur within that free space.
We presented our findings to OCZ, but the company declined to comment. The inner workings of SSDs are not something that vendors like to dish on. However, OCZ has stated on its forum that the Vertex 4 employs two modes of operation: “performance mode” and “storage mode,” and that the drive is behaving as intended.
Update (6/27/2012): OCZ provided us with an official statement to clarify the behavior if its Vertex 4 armed with the latest firmware. We have not yet confirmed how long it takes the drive to transition back and forth from performance to storage mode and vice versa:
“Prior to the development of firmware 1.4 OCZ has been gathering usage data patterns for quite some time and between selected test case customers and internal SSD usage there are several trends that have repeatedly surfaced that we wanted to address directly with this latest update. One of these is that SSDs, more often than not, have large percentages of unused space. Examples include users leveraging SSDs as boot drives, for their hot data or simply for their more performance oriented applications. In the 1.4 firmware release OCZ leveraged these findings and optimized our garbage collection to provide a significant performance boost to users that fall into this category. Effectively what this means is that drives that are less than half full will enjoy further optimized performance and after crossing more than half full the garbage collection algorithm will re-optimize the drive for maximum efficiency based on a larger data footprint. During this transition there may be a small latency hit, but this is a onetime event, and overall performance quickly improves as the drive is now optimized for the larger amount of storage. OCZ feels that this firmware optimization further enhances the overall SSD experience for our customer base.”
From our observations on a partitioned drive, “storage mode” is encountered when sustained write activity exceeds 50% of the available free space. We can only speculate as to why write performance drops. We suspect that the Vertex 4 uses a very aggressive form of garbage collection that needs available capacity to work effectively, although that only partially explains some of our observations. The only way to avoid “storage mode” is to partition the drive to enable 50% over-provisioning.
While we haven't yet tested the 256 GB Vertex 4, we are led to believe that it doesn't take the same performance hit (though that might be due to the fact that a 256 GB drive is more likely to have more free space than a 128 GB drive). We also believe this issue is related to the customized firmware that OCZ uses and is unrelated to the Marvell controller within.
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This is unfortunate. I purchased four of these drives and configured them in RAID 10. I wanted the read performance and the security of knowing I would not have to reinstall everything if a drive failed. I understood I would only have double write performance. But now that I have about 100GB of free space left, I am realizing only single drive write performance. Now I will have to rebuild into a RAID 0 and do regular image backups. :(Reply
What is with these games these vendors are playing with firmware. Sandforce has a trick with compressible data, indelix controllers now expects you to have half your drive empty to get the performance boost?!?Reply
Why can't you just get the consistent performance like you do on samsung 830's ad crucial m4's, there is nothing wrong with consistency.
Thats too bad.:(Reply
i was almost on the point of buying a 128GB Vertex4.
NOT NOW. will wait for the next 1.5 firmware.
its strange that such type of behavior was documented on Toms only, while multiple other sites have already reviewed this drive with 1.4 fw, giving it a very good rating.
+1 to Toms review team
so let me get this.. just like vertex III max iops and regular edition there is a performance drop? I sworn this drive had no garbage collection? either way I may buy one, and wait on 1.5. might as well or wait till I see 1.5 firmware.Reply
Man I was really interested in seeing what Indilinx could do, and I've been recommending this drive on all high end builds. I was even thinking of replacing my Intel 320 with one. Guess I'll be sticking with the Crucial M4 and Plextor M3 from now on.Reply
According to OCZ this is the way the firmware for the Vertex4 128GB is designed to work and part of the reason is because of the way MS made the NTFS file system. They say the SSD will only slow down for a short time and then go back up to near normal speeds.Reply
They also tell me that Tom's Hardware is actually aware of this.
Read about it here: http://www.ocztechnologyforum.com/forum/showthread.php?102254-Anormal-128GB-Vertex-4-Performance
danielkrThis is unfortunate.I read that RAID doesn't support TRIM (never checked beyond that) so I've not bothered with it. Have you done any tests with this?Reply
Todd SauveAccording to OCZ this is the way the firmware for the Vertex4 128GB is designed to work and part of the reason is because of the way MS made the NTFS file system. They say the SSD will only slow down for a short time and then go back up to near normal speeds.Reply
I am sorry, but there should be never be a slow down, this is ssd, people expect top speed all the time from their drives.
you guys releaize that all ssds slow down when they're half full?Reply
edlivianWhat is with these games these vendors are playing with firmware. Sandforce has a trick with compressible data, indelix controllers now expects you to have half your drive empty to get the performance boost?!?Why can't you just get the consistent performance like you do on samsung 830's ad crucial m4's, there is nothing wrong with consistency.Reply
Reading Comprehension Fail... Let say you have a 20 Gigabytes of Free Space (The SSD has 512GB total).
If you try to write a file that is more than 10 GB you'll experience less than optinum performance.
Note we are talking about Sequential Writing.