Crucial announced worldwide availability of its next-generation solid-state drive back in April of 2011. Known simply as the "m4", the company's latest entry is hailed as the successor to its award-winning RealSSD C300, promising to deliver more speed and higher capacities.

The C300 was somewhat of a milestone for the consumer SSD market, being the only flash drive available with SATA 6Gb/s support for quite some time. Whereas most SSD makers opted for the SandForce SF-1200 controller with a peak read rate of 285MB/s, the C300 could hit speeds of 355MB/s courtesy of its Marvell "Van Gogh" 88SS9174 chip.

On top of excelling at sequential throughput, the C300 provided strong random performance when working with files of all sizes, making it a well-rounded contender. However, it's been more than a year since the RealSSD C300 landed, and a lot has changed in that time. Above all, the latest SandForce SATA 6Gb/s controllers have been a real game changer.

OCZ has undoubtedly delivered the finest SandForce-based product in the current generation. Powered by the SF-2281, the Vertex 3 (240GB) offers read and write speeds of up to 550MB/s and 520MB/s.

While the Vertex 3 is representing things on the SandForce front, Intel launched its performance-oriented SSD 510 Series, touting reads and writes of 500MB/s and 315MB/s. The 510 Series surprised us a bit as it's outfitted with Intel's dated 34nm MLC NAND flash chips and a Marvell 88SS9174 controller instead of an Intel-made chip.

Interestingly, Crucial has also decided to equip its m4 drives with the Marvell 88SS9174 controller, though the company has opted for more cost-effective 25nm flash memory. As a result, the 256GB model is currently fetching $1.46 per gigabyte, while the 250GB version of the Intel SSD 510 Series is considerably more expensive at $2.30 per gigabyte.

Firmware plays a vital role for SSD’s and it can really make or break them. The latest generation SandForce SSDs were been plagued by a Firmware bug that would cause random BSOD errors. It took many months for this issue to be solved and in the meantime many users were left with unstable systems.

Since its release the m4 has seen a number of important firmware updates that have improved the drives in a number of ways. Thankfully Crucial was not plagued by stability issues like SandForce partners, making the m4 a success from the start. That said, a recent bug which would case system crashes after 5184 hours was quickly fixed and has been labeled the 5200 bug.

The 5200 bug firmware version has been called 0309. Yet before this version Crucial released a 0009 version which claimed improved throughput performance and write latency. Drives with this firmware version were said to be 20% faster than drives using previously released firmware. Therefore today we are going to revisit the Crucial m4 with the latest 0309 firmware which also carries the performance improvements of the 0009 version.

The m4 utilizes the Marvell 88SS9174 controller along with a large Micron 256MB cache to improve small write performance and eliminate any 'stuttering' issues. This has effectively been doubled from the C300's 128MB cache.

The m4's flash NAND memory is made by Micron, which is unsurprising considering Micron owns Crucial. Our 512GB review unit is equipped with 16x32GB 25nm chips (29F256G08CJAAB) and features Micron's high-speed ONFI 2.1 NAND interface for 166 MT/s with 512-byte industry standard sector size. The 512GB version shows up as 477GB once formatted in Windows.

Crucial says its m4 series has a MTBF (Mean Time Between Failures) of 1.2 million hours, which is somewhat more conservative of an estimate than the ~1.5 million hours you'll find on most other SSDs. To accompany the usual MTBF figure, Crucial also provides a drive endurance rating for each model.

The 64GB m4 is supposedly good for 36TB of data, while the larger models have a rating of 72TB. While that might not sound too impressive, 72TB breaks down to an average of 40GB per day for five years, which is quite a bit for standard use. Besides, the m4 will be ancient history in five years anyway.

In terms of physical durability, Crucial claims that the m4 offers a shock resistance of 1500G, and that's pretty typical among competing flash products. The company's new drives can also operate reliably at temperatures of up to 70 degrees Celsius and will survive 85 degrees when non-operational.

Like all SSDs, the m4 cites very low power consumption figures. At idle, all four models use less than 100mW. When active, the 64GB and 128GB versions consume just 150mW, while the 256GB and 512GB models have a rating of 160mW and 280mW -- the latter of which is still exceptionally low.

The m4 series measures 100.5 x 69.85 x 9.50mm and weighs 75 grams. The drives are compatible with both laptops and desktops, though you'll need an adapter if your chassis doesn't have a 2.5" bay. They'll also work in RAID if you buy more than one and are backed by a limited three-year warranty.

Hardware - Intel Core i7-2600K (LGA1155) - x2 4GB DDR3-1600 G.Skill (CAS 8-8-8-20) - Samsung Spinpoint F1 1TB 7200-RPM (Serial ATA 3Gb/s) - Asus GeForce GTX 580 (1536MB) - Asus P8P67 Deluxe (Intel P67) - OCZ ZX Series (1250w) Software - Microsoft Windows 7 Ultimate (64-bit) - Nvidia Forceware 280.26

In addition to our featured storage devices, the Hitachi Deskstar 7K1000.C 1TB 3.5" 7200-RPM hard drive has been included for comparison purposes.

For comparison purposes we have included SSDs using a wide range of different controllers. Our testing suite consists of four synthetic benchmark programs and our own file copying and load time tests.

As you should know by now, the problem with testing SSDs is that while the manufacturer claims impressive peak I/O performance out of the box, this performance can diminish over time. Unlike a conventional hard drive, any write operation made to an SSD is a two-step process, first the data block must be erased and then written to. Obviously if the drive is brand new and unused there will be nothing to erase and therefore the first step can be bypassed, but this only happens once unless the drive is trimmed.

In consideration of this, we will test how much performance you can expect to lose from each SSD over time. We will test all drives in their clean unused state and then run the HD Tach full benchmark several times, which fills the entire drive. This simulates heavy usage and gives us a clear indication of how performance will be affected in normal long-term use.

Having said all that, all drives support the Windows 7 TRIM function, which is meant to counteract these negative effects in the long run, so it will be interesting to see how the drives perform against each other.

For our 6GB ISO test we take a single large file and duplicate it on the disk. The test is run three times and the average result is recorded, more often than not the three runs are very much the same.

As you can see the updated version of the Crucial m4 is much faster, averaging 169.4MB/s making it 14% faster. This performance gain means that the m4 was now faster than the SandForce SF-2281 drives in this test.

The program copy test is made up of many small non-compressed files. This is where SSDs typically struggle and in the past cheaper drives have proven to be slower than traditional hard drives. Our reference Hitachi 3.5” desktop hard drive managed to provide a throughput of just 28MB/s.

When we first tested the Crucial m4 we found that it was a lot less impressive in our program copy test, providing a throughput of just 139.8MB/s. Well the updated version was no better as it managed just 138.1MB/s, making it a fraction slower.

The game copy evaluation is comprised of a mixture of small and large files. The Crucial m4 performed a lot better in our game copy test though again the updated version was a fraction slower than the original, which was suprising.

The Windows 7 boot time test begins from the moment the initial loading screen appears to the time the Windows desktop's fully loaded. As you can see all SSDs perform exceptionally well here and surprisingly there is very little difference between them.

The updated Crucial m4 was able to load Windows 7 roughly 8% faster than the original version, taking just 9.6 seconds, making it one of the fastest SSDs we have ever tested.

For the application load test we load the following applications into the Windows 7 startup: Internet Explorer, Outlook 2007, Access 2007, Excel 2007, PowerPoint 2007, Publisher 2007, Word 2007 and Photoshop CS4. The test starts when the Windows 7 startup sound loads to the time the final application is loaded.

The Windows 7 multitasking performance was slightly improved as the updated drive was 0.3 seconds faster, which was almost a 6% performance gain.

This test measures the time it takes to load Adobe Photoshop CS4 from the time we click on the icon to the time the program is completely loaded and ready to use.

When we originally tested the Crucial m4 in our Adobe Photoshop CS4 load test we found it to be quite slow. However the updated version was able to match the fastest drives tested, taking just 1.2 seconds.

This next batch of results was recorded when loading the last level from the single campaign in StarCraft II. The test began the second the load screen appeared and was stopped once the “click to play” message appeared.

When compared to the original the updated m4 was 15% faster in our StarCraft II level load test. The m4 took 16.5 seconds, making it slightly faster than the Samsung 830 Series, yet slightly slower than the older Samsung 470 Series.

The CrystalDiskMark sequential read test saw a 34% performance improvement from the updated Crucial m4 drive, as it delivered an extra 136.7MB/s. This made it faster than any other SSD tested to date. While the read performance was drastically improved, the write performance was only slightly boosted as the updated model was just 4% faster.

The random 512K read results also saw a massive performance increase in favor of the updated model, as it provided 43% more performance delivering an extra 136MB/s. The write performance was again much the same, with the updated model only providing a very slight improvement.

Finally the 4K-QD32 test where we found the updated Crucial m4 drive to deliver 24% more performance in the read test. Again the write performance was much the same, though the small performance increase did put the m4 on par with the Vertex 3.

The Atto Disk Benchmark shows that the updated Crucial m4 drive delivers similar performance when working with 1K and 2K data to that of earlier revisions. However once we reach 8K and beyond the performance gain is quite considerable and the m4 is able to keep pace with and even beat the Vertex 3.

Here we see that the write performance of the updated Crucial m4 drive goes virtually unchanged and when working with 8K data and larger the m4 is quite a lot slower than the Vertex 3.

It was the same case when testing the new SandForce SF-2281 drives, such as the OCZ Vertex 3, and they turned out to be quite unstable suffering from BSOD (Blue Screen of Death) errors. Although the SandForce drives have now been corrected via a new firmware release, users had to live with numerous bugs for many months.

The Crucial m4 series on the other hand has been relatively bug free, with the only issue we are aware of being the 5200 hour bug which was quickly squashed. For the past 9 months I have used a 256GB model of the m4 in my own office computer and I am yet to have any problems with it.

Today the Crucial m4 is even better as firmware updates have fine-tuned the performance, allowing it to better compete with the speedy SF-2281 drives. The 512GB version of the m4 that we reviewed was exceptionally fast, providing rapid Windows 7 boot times and lightning fast multitasking performance.

Although the file copy performance wasn’t really improved, we still found the m4 to be very fast. The reason we didn’t see any performance gains here is because the copy tests reads and writes simultaneously and since the write performance of the m4 didn’t look to be improved the gains were limited.

Performance aside, if I were going to invest my money in an SSD today the Crucial m4 would be at the top of my list simply because it’s a safe investment. It also helps that the drives are relatively good value, at least as far as SSD prices are concerned. The 128GB and 256GB models sell for just $1.42 per gigabyte, while the 512GB version is even more affordable at $1.39 per gigabyte.

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In contrast the Vertex 3 range costs $1.58 per gigabyte for the 120GB and 240GB models, while the 480GB version is fetching a whopping $2.29 per gigabyte, making it significantly more costly than the Crucial m4 512GB. In fact while the m4 512GB costs $714, the Vertex 3 480GB costs a whopping $1100.

Embarrassingly I have to admit while I was unimpressed with the m4 series upon launch, as the read and write speeds seemed lack luster in comparison to the SandForce SF-2281 drives, they have managed to hold their own and proven to be the smarter investment in the long run.