The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
New vs Used SSD Performance
We begin our look at how the overhead of managing pages impacts SSD performance with iometer. The table below shows iometer random write performance; there are two rows for each drive, one for “new” performance after a secure erase and one for “used” performance after the drive has been well used.
| 4KB Random Write Speed | New | "Used" |
| Intel X25-E | 31.7 MB/s | |
| Intel X25-M | 39.3 MB/s | 23.1 MB/s |
| JMicron JMF602B MLC | 0.02 MB/s | 0.02 MB/s |
| JMicron JMF602Bx2 MLC | 0.03 MB/s | 0.03 MB/s |
| OCZ Summit | 12.8 MB/s | 0.77 MB/s |
| OCZ Vertex | 8.2 MB/s | 2.41 MB/s |
| Samsung SLC | 2.61 MB/s | 0.53 MB/s |
| Seagate Momentus 5400.6 | 0.81 MB/s | - |
| Western Digital Caviar SE16 | 1.26 MB/s | - |
| Western Digital VelociRaptor | 1.63 MB/s | - |
Note that the “used” performance should be the slowest you’ll ever see the drive get. In theory, all of the pages are filled with some sort of data at this point.
All of the drives, with the exception of the JMicron based SSDs went down in performance in the “used” state. And the only reason the JMicron drive didn’t get any slower was because it is already bottlenecked elsewhere; you can’t get much slower than 0.03MB/s in this test.
These are pretty serious performance drops; the OCZ Vertex runs at nearly 1/4 the speed after it’s been used and Intel’s X25-M can only crunch through about 60% the IOs per second that it did when brand new.
So are SSDs doomed? Is performance going to tank over time and make these things worthless?
"Used" SSD performance vs. conventional hard drives.
Pay close attention to the average write latency in the graph above. While Intel’s X25-M pulls an extremely fast sub-0.3ms write latency normally, it levels off at 0.51ms in its used mode. The OCZ Vertex manages a 1.43ms new and 4.86ms used. There’s additional overhead for every write but a well designed SSD will still manage extremely low write latencies. To put things in perspective, look at these drives at their worst compared to Western Digital’s VelociRaptor.The degraded performance X25-M still completes write requests in around 1/8 the time of the VelociRaptor. Transfer speeds are still 8x higher as well.
Note that not all SSDs see their performance drop gracefully. The two Samsung based drives perform more like hard drives here, but I'll explain that tradeoff much later in this article.
How does this all translate into real world performance? I ran PCMark Vantage on the new and used Intel drive to see how performance changed.
| PCMark Overall Score | New | "Used" | % Drop |
| Intel X25-M | 11902 | 11536 | 3% |
| OCZ Summit | 10972 | 9916 | 9.6% |
| OCZ Vertex | 11253 | 9836 | 14.4% |
| Samsung SLC | 10143 | 9118 | 10.1% |
| Seagate Momentus 5400.6 | 6817 | - | - |
| Western Digital VelociRaptor | 7500 | - | - |
The real world performance hit varies from 0 - 14% depending on the drive. While the drives are still faster than a regular hard drive, performance does drop in the real world by a noticeable amount. The trim command would keep the drive’s performance closer to its peak for longer, but it would not have prevented this from happening.
| PCMark Vantage HDD Test | New | "Used" | % Drop |
| Intel X25-M | 29879 | 23252 | 22% |
| JMicron JMF602Bx2 MLC | 11613 | 11283 | 3% |
| OCZ Summit | 25754 | 16624 | 36% |
| OCZ Vertex | 20753 | 17854 | 14% |
| Samsung SLC | 17406 | 12392 | 29% |
| Seagate Momentus 5400.6 | 3525 | - | |
| Western Digital VelociRaptor | 6313 | - |
HDD specific tests show much more severe drops, ranging from 20 - 40% depending on the drive. Despite the performance drop, these drives are still much faster than even the fastest hard drives.
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matrixireland - Thursday, December 24, 2009 - link
hi would like to know what you pros think of the;Golden Leopard ASAX-ZIF1.8-SSD? what would you add to it?
And how would you rate it against other ssd?
Specifications:
product description
ASAX-ZIF1.8-SSD is a high-performance design solid state drive based on the high-end micro-control IC with flash memory storage medium integrated advantaged of high speed,convenient ,aseismatic,energy-saving etc.
specification
Model
Size
Interface
Material
ASAX-ZIF1.8-SSD
1.8inch 70×54×6mm
ZIF
Aluminum-magnesium alloy appearance ,drawbench and colorful oxidation surface,elegant temperament
performance
read speed:80- 96Mbytes/second write speed:50- 60Mbytes/second
support ATA-7 V3 PIO/multi word/ultra DMA MODES
Low power TFBGA,4 channel of flash controller,masked ROM and data SRAM
SAMSUNG flash keeps the data faster on reliability and endurance
Dynamic and static wear-leveling prolong NAND FLASH and SSD for longer life
8/16 bit BCH ECC data error correction ability effectively guarantee the data read security.
Design consideration
Capacity
16G/32G/64G/128G/256G
Average access time
<0.25MS
operating temperature
0-85°
power consumption
DC Input Voltage(3.3V or 5 V ± 10%)Read and write:135mA/194Ma wait:70mA
shock
1500G
Application
the Laptop, pc, server,workstation,portable media player,digital collection apparatus and any computer equipment which need consecutive read and write speed and high reliability storage.
jay401 - Wednesday, March 18, 2009 - link
yeah, he wants "more expensive than" or "too expensive for".Spoelie - Wednesday, March 18, 2009 - link
Second page as well:missing charts before and after this paragraph:
"The chart above shows how much faster these affordable MLC SSDs were than the fastest 3.5” hard drive in sequential transfers. But now look at random write performance:"
Spoelie - Wednesday, March 18, 2009 - link
chart 1 on page 2 now shows sequential read but the paragraph is changed to mention random read ;)page 21: As far as I know, this is THE one of THE only reviews
Some very surprising benchmark results for the ocz vertex, I thought the new firmware tanked sequential read speeds (to 80-90) based on the explanation beforehand, but not according to the actual graphs.
Spoelie - Wednesday, March 18, 2009 - link
third page, first table, first column: SSD and HDD entries are switchedmikaela - Tuesday, March 16, 2010 - link
yeah great info. also great resourceSpoelie - Wednesday, March 18, 2009 - link
page 19: I’d never reviewed it'd & -ed?
HolyFire - Wednesday, March 18, 2009 - link
"I'd never reviewed it" is correct. "I'd" here means "I had", it's Past Perfect tense.FishTankX - Wednesday, March 18, 2009 - link
That should have bolded "too"FishTankX - Wednesday, March 18, 2009 - link
Also, I think the velociraptor vs X-25 figures are swapped. 6 odd ms for the intel drive and 0.11ms for the velociraptor..