Introduction
Native PCIe-based drives are to SSDs what SSDs are to hard disks. With a direct link to the CPU, PCIe-based storage further reduces latency, increases available throughput and gives enthusiasts the best experience you can buy. Unchained from the limitations of SATA, the products we're testing deliver up to 4x the performance of previous-gen SSDs that slammed into a ceiling at 6 Gb/s.
PCIe storage isn't a new concept. In the past, solutions like OCZ's RevoDrive tapped the PCIe bus as well. Until recently, the golden example was actually from Fusion-io, which made one of the first native PCIe-to-flash controllers. The RevoDrive sought to serve up Fusion-io-like performance. But, in order to keep costs low, presented a PCIe-based SATA/SAS RAID controller in front of multiple SATA SSDs. It delivered high throughput for fast sequential reads and writes, but lacked Fusion-io's low latency for the quickest random data accesses.
Native PCIe is the key. You can think of the SSD controller as a bridge. In this case, the controller connects the CPU's PCIe connectivity to the NAND flash, which holds the data. All-in-one RAID products like the RevoDrive and G.Skill Phoenix Blade take PCIe to a RAID controller, and then through several SATA interfaces to the solid-state storage. The extra hops increase latency, add cost and reduce efficiency.
In order to remain focused, we're limiting the number of products compared today. Right now, Intel's SSD 750 series and Samsung's SM951 are in a unique position. This is the story that power users and enthusiasts have asked for, a showdown devoid of fluff and filler.
Intel recently released its SSD 750 series in two capacities. But the launch didn't go as smoothly as it could have. Reviewers tested the 1.2TB that sells for more than $1000. We called it The Extreme Edition of SSDs. If you need lots of capacity and can afford the high cost of procurement, then rest assured that Intel's big SSD 750 is the largest drive in this performance class. For the rest of us, Intel introduced a 400GB model priced just over $400. At over $1/GB, that's still nowhere near cheap.
The only direct competitor to Intel's native NVMe-capable SSD is Samsung's SM951 512GB, which used the AHCI standard when it was released, but will leverage NVMe in the near future. For now, the AHCI models in 128, 256 and 512GB capacities are all you can get. Despite the difference, we've been inundated by readers asking which of the two SSDs is better. Today we'll present an answer.
