Closer Look at Corsair Neutron and Corsair Neutron GTX
Having laid their hands on the highly promising LAMD LM87800 controller, people at Corsair decided to use it in two products series targeted at different price segments. The Neutron GTX series includes flagship products with maximum performance while the ordinary Neutron is positioned as a midrange solution. The price gap is distinct: Neutron SSDs cost $0.8 to 1.0 per 1 gigabyte of storage whereas Neutron GTX models cost $1.0 to 1.2.
The two series are similar in their interior design, though. Both use the same controller modification and eight-channel flash memory with synchronous interface. The difference boils down to the flash memory brand and the interface type. The midrange models use widespread 25nm ONFI flash whereas the flagship ones are based on 24nm flash with Toggle Mode interface.
The following table helps you compare their speed characteristics:
The two series differ considerably in terms of their sequential write speed. The Neutron GTX products are going to be competitive against the fastest SSDs with other controllers but the ordinary Neutron drives will be inferior to today’s leaders. On the other hand, the new SSDs from Corsair all feature a very high speed of random reading, which is perhaps the most important parameter as it affects performance in typical usage scenarios. Considering this and the fact that the GTX and ordinary Neutron drives only differ in flash memory interface, we can expect the two series to be very close in practical performance. The GTX version with increased writing speed may be interesting for enthusiasts as it will surely help get high results in synthetic benchmarks.
The storage capacity parameter must also be noted. The two series of new SSDs from Corsair both come in capacities of 120 and 240 gigabytes which are typical of the SandForce platform and indicate that about 13% of the total capacity is not available for the user. The reserve pool is used for wear leveling and replacing failed flash memory cells. It also improves the efficiency of the garbage collection technique and seems to be one of the means that help increase the service life of the resulting product as promised by LAMD. Corsair agrees with the controller developer and emphasizes the high reliability by providing a 5-year warranty on every Neutron and Neutron GTX drive. Thus, the number of consumer-class SSDs with extended warranty is on the rise. Such models are available from Intel, Plextor, OCZ and now from Corsair too.
One more distinctive feature of LAMD-based SSDs is the little variation in storage capacities. In fact, the Neutron GTX and Neutron series come in two versions only: 120 and 240 gigabytes. And we cannot expect more for two reasons. First, the LM87800 controller does not support asymmetric flash memory configurations and thus cannot be used for 90 or 180GB drives. And second, the number of NAND devices on each controller channel is limited to 4, so SSDs larger than 240 GB cannot be built using today’s 64-gigabit flash memory chips. Corsair wants to overcome this barrier, however, by introducing additional multiplexor chips and promises to eventually release 480GB Neutron GTX and Neutron drives.
Thus, the 240GB models we’ve received for our tests are the top-end offers in their respective series and are likely to stay that way in the near future. Let’s take a closer look at them now.
The Neutron GTX 240GB and the Neutron 240GB are shipped in similarly designed cardboard boxes which differ in color. Red is the color of the GTX series whereas the ordinary series is blue.
We can see a picture of the SSD, series logo and basic specs on the front of the box. On the back there is just some advertising text, a sticker with barcode and part number and a small window that lets you compare the part number with what is written on the SSD itself.
The SSD is fixed in a stiff plastic blister wrap which protects it from any damage during transportation. Besides the SSD proper, the box contains some mounting screws and an adapter for installing the 2.5-inch drive into a 3.5-inch bay of a system case.
Corsair has changed its SSD case design along with the introduction of the LAMD controller. The new case has a height of only 7 millimeters which means that Neutron GTX and Neutron drives can be installed not only in desktop PCs and standard notebooks but also in ultrabooks and other highly portable devices. The only external difference between the Neutron GTX and the Neutron is the label with logotypes, capacity information and part number.
The new case seems to be inferior to the old design in quality. It is less robust, its halves being fastened to each other with simple locks rather than screws. Obviously, besides the reduced height, the new case has been designed to be cheaper to make. Well, anyway, it is the internals that’s important, not the exterior.
The Neutron GTX and Neutron have completely different PCBs. The only thing they have in common is that they are both small and carry a LAMD LM87800 controller together with a 256MB cache consisting of two DDR2-800 SDRAM chips from Samsung. In both SSDs the controller has contact with the metallic case via a thermal pad. The chip is hot at work, so this solution helps cool it well. There’s a temperature sensor for monitoring. Many consumer-class SSDs lack this feature.
The senior version, Neutron GTX, has eight flash memory chips from Toshiba. These are 256-gigabit chips with Toggle Mode interface, each of which contains four NAND devices manufactured on 24nm tech process. By the way, similar chips are installed into same-capacity Plextor M3 Pro drives with the Marvell 88SS9174 controller. In both cases the controller uses 4-way interleaving for memory access. Coupled with the high bandwidth of the Toggle Mode 2.0 interface, this should make the Neutron GTX fast in benchmarks.
The junior Neutron has twice the memory chips: 128-gigabit chips of synchronous flash with ONFI interface manufactured by Micron. Each chip contains two 25nm NAND devices, so the controller can use 4-way interleaving, just like in the Neutron GTX. The Neutron is going to be slower because the ONFI 2.x interface has lower bandwidth than Toggle Mode 2.0.
The two SSDs from Corsair have the same firmware. It is version 2.06, although the products have just hit the market. Hopefully, the high version number indicates thorough presale testing and lack of serious firmware flaws.