OCZ Agility SATA 2.0 SSD 120GB
Phoronix: OCZ Agility SATA 2.0 SSD 120GB
Back in May we reviewed the OCZ Vertex SSD, which performed well against a Super Talent SSD and two different rotating mobile HDDs. This OCZ SSD was not exactly cheap but it was not too expensive either and it ended up receiving our Editor's Choice award. Since then, OCZ Technology has introduced the Agility SATA 2.0 Solid-State Drives. The Agility is designed to fill OCZ's mainstream SSD offerings with models up to 120GB in size, MLC flash memory, 64MB cache, and slightly better prices. In this review we are testing out the OCZ Agility 120GB Serial ATA 2.0 SSD, under Ubuntu Linux, of course.
I have a another theory on why the Agility managed to beat the Vertex.
Firstly, the Agility series ships with the 1.30 firmware version, which is availible as an update to the Vertex, while your Vertex only was updated to 1.10.
Secondly, from the article into it sounds like you are using a brand new Agility, but a used (though reformated) Vertex, and it's well known that SSD disks starts to perform slightly worse when they "age".
These two factors taken tokether is probably the reason that the Agility performed better than the Vertex.
You can make any product look good, depending on what you compare it with. Where is the Intel X-25 E in this head-to-head? Sure it is only 32 Gb, but the other competitors in this race are also not true "competitors" as their capacities are not the same as the reviewed unit.
When I see disk benchmark comparisons on other sites, they usually report the CPU utilization as well. Why not here?
It seems to me that the policy is to choose competitors so that the reviewed product always comes out on top. I suppose this makes the manufacturers of the reviewed products happy, but it does not serve the readership well.
Half of these benchmarks are gratuitous CPU bound tasks where we could all predict the results without looking, but hey, they generate page hits.
I'm glad someone else noticed! Getting quite fed-up with these half-assed reviews...
Originally Posted by Jonno
Formatting does NOT reset the disk!
Then what would actually reset the disk?
Originally Posted by tomm3h
dd if=/dev/zero of=/dev/sdX ?
No, there are vendor tools that allow setting the drive to a state in which all data is unused. That means that for new data no old data has to be read and written together with that. Without that extra read that's of course faster. Therefore the same disk can perform completely different then it was 100% filled before. Normal hds suffer from fragmentation, that's usally no problem there, when you defrag a ssd then you "fill" it, which would make it slower. New os like Win7 or maybe some Linux kernel versions allow the use of special delete commands to recover a used sector but i don't think that dd will use those...
The reason why 120gb OCZ agility beats 60gb OCZ vertex is because they are different sizes.
The 120gb versions of vertex, agility, turbo, summit etc, are all the fastest versions.
In order of speed:
1. 120gb versions
2. 250gb versions
3. 30gb and 60gb are tied.
This is what OCZ representative has stated on their forum, and what specs and benchmarks have shown.
The flaw in benchmarking 120gb agility and 60gb vertex makes agility look much better than vertex which is not the case. Well it is when comparing different sizes, but you misrepresent it in your review in making agility series look better than vertex series.
The only good thing about this review is that is compares two different speed (based on size) SSD, to show the difference between 30/60gb models and the far superior 120gb model. At least people will get a view of speed difference in size models and thus decide whether to buy 120gb version for more speed. Cost per gb is better at 120gb models as well.
If you had reviewed 60gb agility with 60gb vertex (or both 120gb), you should have noticed the speeds would have been about the same for both.
You should definitely add to your article that the 120gb versions are faster than 60gb version regardless of whether it is vertex or agility etc. This makes very unfair comparison and misleading. As long as you point this out it would make the review fair and a worthwhile read so people know the speed differences between 120gb models and 60gb models. Also it is possible the agility you got has a faster chip than other agility, since agility can use several different types of chips (they hand pick them), so speed can be slightly different with each product. Meanwhile vertex uses a single chip, so they would all be identical.
As there are only a few real ssd manufacturers you can get the same with a different branding and price. Just a bit tricky to find out who created em. For intel ssds the intel logo will be still somewhere even if it was produced for oem, others may be harder to identify. OCZ was always oem - they bought ram modules and hided the real manufactors with a cooler. That's the usual way.
TRIM is supported by ext4 (dunno about ext3) since Linux 2.6.30 or 2.6.31. But there is still no SSD avaible that supports this command. Firmware updates for Intel and probably the Indilinx are coming September/October-ish.
Originally Posted by Kano
Originally Posted by tomm3h
No, as SSD disks differentiate between empty blocks and block with zeroes on it. To write data to an empty block is an easy operation, but to write data to a used block (including a zeroed block) requires the entire erase block (usually consisting of several hundred write blocks) containig it to be erased, and then rewritten again (with new data in that single changed write block). And after that operation all blocks are still used, so the whole procedure has to be done again for the next write block. Write caching will of course help somewhat, but only if multiple writes to the same erase block happens close enough to each other. This is the major factor making random writes hundreds of times slower than sequential writes on SSDs, even though there is no seek latency.
Originally Posted by Zhick
TRIM is a relatively new addition to the ATA standard that tells the drive that you are not interested in a block any longer, and the drive can go ahead and erase it whenever it has nothing else to do (or just skip rewriting it the next time it is forced to rewrite the erase block). However, hardware vendors don't dare ship a firmware with TRIM support before they have tested that it works in Windows 7 (the first MS OS with TRIM support), and Linux developers don't dare add TRIM support to the kernel untill they have tested that it works on actuall drives. Becouse if you get TRIM wrong, you'll lose user data for sure, and no one likes that. Thus no TRIM support until later this fall.
Future versions of mkfs.* will hopefully get TRIM support, so that reformating a drive realy does reset the drive to a brand new state, but right now it doesn't, it has no effect on the performance of a drive. Your dd trick, on the other hand, is actually a good way of forcing the drive to a "used" state where it will perfom at it's worst (becouse all blocks have been written to).
As most disks won't stay brand new for long, "used" performance is actually way more insteresting than "new" performance, so Phoronix should have done that dd trick on both drives before conducting their tests (though I would have used /dev/random just in case the firmware tries to be smart with zeroed blocks, wich isn't likely, but not implausible either). After updating the Vertex firmware to 1.30 of course.
As stated by others, disk sizes can have a speed impact as well, so comparin the same size would have been more honest, though comparing a 60GB Vertex with an only slightly more expensive 120GB Agility would be interesting as well, if all else was equal. As it stand, this particular benchmark is worse than useless however.