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Gone in a Flash - 5 Solid State Drives Compared

Gone in a Flash - 5 Solid State Drives Compared



A Quick Flash Premer

SSD Drives - The Next Big Speed Boost

These days, upgrading to a new processor or adding more memory than required doesn't quite give you the same tangible feeling you once had when upgrading from a Celeron to a Pentium III. Platforms have progressed so much that the next big bottleneck in performance in a non gaming and non compute intensive context happens to be your storage drive. You get a much bigger perceived performance boost by upgrading your hard drive than upgrading from a dual-core to a quad-core processor.

Remember the speed boosts that you got from moving from a lowly 5400rpm drive to the 7200rpm drives, and in more recent times with the 10,000rpm drives? If those sound good, prepare to get a far bigger boost when you take the leap to solid state drives (SSD). Read on for our assessment of some of the fastest SSD drives money can buy and our findings. But just before that, we give you a primer on the state of SSD drives.

A Quick Flash Primer

The person who first coined the term 'flash memory' wanted to illustrate the speed of erasing the contents of the memory, which happens as quick as the 'flash' of a camera. Which is accurate, since flash memory involves manipulating voltages to change the internal state of the transistors within the memory cells and all that occurs on the scale of microseconds.

More than twenty years later, flash memory has moved from its initial use in ROM chips to becoming the future storage medium of choice for its speed and durability. As predicted by this article featuring its inventor, NAND flash has come to dominate the market and is now the latest trend in storage media.

While its cost has been prohibitive in the beginning, it has now dropped to a level that is acceptable to certain groups of users. Flash-based portable thumb drives are about as common as optical mice these days and solid state drives (SSD), the next frontier for flash memory storage has reached the consumer desktop in increasing numbers, especially in high-end notebooks.

The Reduced Cost of MLC

Besides the increased manufacturing capacity and advances in NAND flash technology, part of the reason for its falling cost is the entry of SSDs that use a different form of NAND flash technology, the Multi-Level Cell (MLC). This differs from the Single-Level Cell (SLC) design that can only hold 1-bit of information in each of its transistors. In MLC flash, the electrical charge applied is varied to create different states (there are four) and this results in 2-bits of information per cell, hence doubling the storage capacity.

The drawbacks however include having slower read and write performance, as due to the closer proximity between the voltages used to distinguish the states, more precautions need to be taken during read or write. However, the biggest difference between the two designs lie in something called memory wear. Basically, all NAND flash memory can only undergo a certain number of erase and write cycles before they wear out completely. For SLC NAND, this is around 100,000 cycles, but for MLC, it's an order of magnitude lower at 10,000. Hence, one usually finds enterprise class SSDs using SLC flash memory and the increasing number of consumer drives using MLC flash memory.

Although technologies like wear leveling ensures that all your memory cells are used as evenly as possible to lengthen the lifespan, it will be inevitable that one day, your SSD will not be able to work as usual. That doesn't mean that your data will be lost; it just means that one cannot write or erase the existing information on the drive. You can still read the drive. This will however take a long time, perhaps a time frame by which a typical hard drive might have either failed or would have been relegated to a lesser secondary role in the hands of the common DIY enthusiast.

It's a Brave New World

But just to illustrate the uncertainty surrounding such new technologies, recent issues emerged that showed Intel's X25-M SSD (which incidentally is part of our review today) slowed down after extensive use while SSDs like OCZ's Core that used JMicron's JMF602 controllers were prone to stuttering due to poor random write performance for small files. Intel has released firmware (which we've used as well) that appeared to have mostly resolved this issue while OCZ has changed tack with a new controller for its latest SSD.

Both the Intel and OCZ drives are in our roundup of some of the best SSDs available in the market now. We've asked almost all the common SSD vendors to send in their top 64GB SSD drives, but apparently for some strange reason only half of them were able to prepare review drives in time for our shootout; too bad for the rest of them. So for this article, we've drives from Kingston, OCZ, Mtron and Patriot, including the odd man out at 80GB from Intel.

While larger capacity drives have more memory channels and thus able to offer even faster read/write speeds, we opted to conduct the comparison for 64GB drives. Given the exorbitant price per gigabyte costs involved for SSD drives, we figured that 64GB is the probable sweet spot for enthusiasts to consider integrating these drives to their rigs for speedy system and application loading purposes. Let's face it, terabyte capacity drives are certainly the requirement for mainstream storage and SSDs won't get to such comfortable price points so soon.

With both SLC and MLC flash memory designs represented in this article, we hope to find out if the latest SSDs have finally shed themselves of teething problems and take up its position as the successor to mechanical hard drives (at least for certain usage scenarios). Here are the contenders with their crucial technical specifications:

Technical Specifications
Model Flash Memory Type Controller Onboard Cache Advertised Sequential Read/Write Speeds
Intel X25-M 80GB MLC Intel 256KB
  • Read: 250MB/s
  • Write: 70MB/s
Kingston SSDNow E-Series 64GB SLC Intel 256KB
  • Read: 250MB/s
  • Write: 170MB/s
Mtron PRO 7500 64GB SLC Mtron 16MB
  • Read: 130MB/s
  • Write: 120MB/s
OCZ Vertex 60GB MLC Indilinx 'Barefoot' 64MB
  • Read: 230MB/s
  • Write: 135MB/s
Patriot Torqx 64GB MLC Indilinx 'Barefoot' 64MB
  • Read: 220MB/s
  • Write: 135MB/s