Intel SSD 520 Series In Detail
The Intel SSD 520 Series is aimed at performance buffs with initial SF-2281-based models offering capacities of 60GB, 120GB, 180GB, 240GB and 480GB. The SSD 520 Series has a slim 2.5" design, measuring 100 x 69.85 x 9.5mm and weighing up to 78 grams. All models except the 480GB version are actually just 7mm thick yet feature a 2.5mm plastic spacer which increases the height of the drives to meet the standard 2.5” specifications.
Using the MobileMark 2007 Workload Intel claims that when active the drives consume just 850mW of power and 600mW when at idle. They claim the same load and idle power consumption for all five models.
The 60GB model packs read and write speeds of 550MB/s - 475MB/s, while the larger 120GB version is slightly faster with 550MB/s reads 500MB/s writes. The 180GB, 240GB and 480GB models are slightly faster again as the write performance is boosted to 520MB/s.
Naturally, using the SATA 6Gb/s interface is essential to achieving those speeds. Currently Intel's Sandy Bridge platforms provides native SATA 6Gb/s support, as does the AMD AM3+ platform.
There are also third party embedded solutions, such as the Marvell 88SE9128, which can provide motherboards with SATA 6Gb/s support, but offer very poor results compared to Intel's implementation. There's also a new Marvell 88SE9182 controller that can mimic the performance of Intel's 6 series chipsets, so support for 6Gb/s SATA is improving.
All five SSD 520 Series models are loaded with Intel MLC NAND (25nm) flash memory. Our review sample has sixteen 16GB Intel 29F16B08CCME2 NAND ICs for a total capacity of 256GB. The reason this is marketed as a 240GB SSD is because 16GB is reserved for data parity (8GB for RAISE), garbage collection, and block replacement. It is also worth mentioning that this is the same flash memory used by the 240GB versions of the OCZ Vertex 3 and Kingston HyperX SSD drives.
Once formatted in Windows, the original 240GB is converted to 224GiB, though Windows shows this as 224GB, so it seems like 7% of the original capacity has been lost. With an estimated retail price of $510, the SSD 520 240GB costs $2.10 per gigabyte, which is a poor value even for a high-performance SSD.
Like the original SF-1222 controller, the second-generation SF-2281 uses data compression technology called DuraWrite. This is designed to help lower write amplification and extend the drive's life by using fewer program-erase cycles. The upside is that this doesn't require a memory buffer, while the downside is that it uses more storage space on the drive.
The same Tensilica DC_570T CPU we mentioned in our Vertex3 review is being used in the SF-2281. Although the CPU remains the same, the compression engine has been improved. The 2nd-generation SandForce controllers have a bigger block of silicon dedicated to DuraWrite technology, while the garbage collection algorithms have also been improved.
Intel has given the SSD 520 Series the same one-million-hour MTBF (Mean Time Between Failure) rating as the SSD 510 Series which is 1.2 million hours. This figure essentially means nothing to the consumer and honestly we really have no idea how reliable these drives are going to be in the very long run. However, the Intel three-year warranty should let customers sleep comfortably at night knowing they're covered for a reasonable timeframe. We'd like to drop a friendly reminder here that this won't protect your data, so be diligent about backups.