Looking back, Intel's 520 Series was the best SSD build using the LSI SandForce SF-2281 controller. Intel was allowed to build its own firmware for the 2281 and as a result didn't need to do the firmware dance. When SandForce need to make big changes to the programming in order to work with 19nm Toggle flash, Intel didn't need to follow the same path because they own a flash fab - well, 49% of it anyway.
Intel, like other SSD manufacturers, chose a two tier approach for the consumer SSD market. The 520 Series holds the top spot, even today, with 25nm ONFi synchronous 5K P/E flash. The value or mainstream SSD product was the 330 Series. The 330 Series also used 25nm ONFi synchronous flash, but with 3K P/E cycles. The 330 is out and the new 335 takes over as the mainstream SSD offering for Intel.
Intel's 335 Series has nearly identical specs to the 330 Series, but ships (as of now) only in 240GB capacity size and uses 20nm synchronous NAND flash. Intel rates the new 20nm flash at 3K P/E cycle just like the 25nm flash used on the 330.
Even though the 330 and 335 share almost identical spec sheets, we expect some improvement in other areas. Intel had an extra year to work on the 335 Series firmware. Firmware and programming are just as important as the hardware used to make an SSD. We also want to keep an eye on latency since latency should increase as the lithography shrinks. The LSI SandForce SF-2281 is the perfect controller to look for increased latency since it lacks a DRAM buffer.