A Closer Look at the Optane Memory Module
A Closer Look at the Optane Memory Module
As I’ve already mentioned the idea behind the new Optane Memory module is rooted firmly in Intel's Smart Response Technology. Much like this circa 2006 technology the Optane Memory module is not an all in one device. Instead it is part of an ecosystem that boosts performance beyond what is capable with Hard Disk Drives and even Solid State Hybrid Drives.
To do this Optane relies upon four parts. The actual Optane Memory module, the Peripheral Controller Hub (PCH), motherboard and OS level drivers, and special software. All five of these critical components are necessary as the Optane Memory module is in simplest terms a M.2 form-factored, NVME PCIe 3.0 SSD. While it can be utilized to mount an OS, Intel does not expect it to be configured as a stand-alone storage device. Instead it is designed to act as a read / write cache storage device that resides between the SATA controller and a system's existing non-volatile storage device.
At this time only Intel PCH's capable of allowing the Optane Memory module to do its indented job are the 2-series chipsets. These include the entry level Q250 and Q270, the more mainstream B250 & H270, and upper tier Z270. Thus, owners of everything from Intel Z170 and X99 chipset based motherboards need not apply – as their controller is not capable of accomplishing what the 2-series chipset does natively.
The motherboard not only needs to be equipped with a 2-series chipset, and a free PCIe x2 M.2 slot, but also its BIOS must be Optane aware. At this time almost all are, but before anyone tries to configure their Optane Memory module they are advised to update to the latest firmware. For example the ASUS Prime Z270-A requires the latest 0906 firmware to work. So check your motherboard manufacturer's website first.
On top of all these caveats, users must also install the latest Intel Rapid Storage Technology (RST) drivers. The version used for this review is 126.96.36.1991 and it is what Intel recommends. This driver is critical for Optane since it not only helps make the memory module 'invisible' to the OS but also redirects the necessary IO requests.
The last piece of the puzzle is the Intel Optane Memory software application. This software not only allows owners to enable or disable caching but also does scheduled house-cleaning of the Optane Memory module's 3DXPoint cells. This is critical as TRIM commands are not necessarily being sent to the OS – as the OS will only see the hard disk drive installed.
At this time Optane Memory modules come in two sizes: a small 16GB for more basic systems (web surfing, basic word-processing, etc.) and a larger 32GB model more capable of handling the requirements which a modern system places on the long-term storage subsystem. Both models use the exact same single sided M.2 2280 form-factor and require two PCIe 3.0 lanes to work. Put in laymen’s terms the Optane Memory module is a small 22mm wide by 80mm long 'stick' that only has components on one side.
To be a bit more precise the 32GB Optane Memory Module consists of three main components: a next generation Intel NVMe controller, and two 3DXPoint ICs. As we discussed in our previous article in greater detail, 3DXPoint is considered non-volatile memory so there is no need for expensive capacitors on the M.2 for data-loss protection. Basically, this cutting edge Single Level Cell memory technology is not only faster and denser than NAND but it doesn’t suffer from data corruption due to unexpected power loss. Instead, when power is restored the data is in the exact same state as it was when the power was lost.
Very little is known about the second-generation Intel NVMe controller used in the Optane Memory series, but as this device can – if you so choose – be used as a standalone SSD some inferences can be made based on empirical data. In testing the 32GB Optane Memory module performed admirably well for its size. It does however suffer from a few design issues that were necessary in order to make it work in everything from low-power Q250 systems to high performance Z270 motherboards.
Basically, by opting for a two dual PCIe 3.0 lane instead of a four lane one, overall throughput is reduced compared to four lane NVMe solid state drives. Also, due to the single sided 80mm form-factor the number of 3DXPoint ICs is also limited. This combines to create a device that has decent -if not amazing for a PCIe drive- sequential performance but rather lackluster small file queue depth throughput.
The most concerning impact of these design decisions is the write speed which is a mere 300MB/s and 60,000 IOPS. This is significantly lower than what even SATA based solid state drives can offer. We will go over the real-world impact in the following pages, but it is significant and does have far reaching implications.
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