SSD Breakdown – What’s on an SSD? Lexar NM760 Showcase

First off I want to make it clear this video is sponsored by Lexar, and in it I’m going to be talking you through the various components on their NM760 PCIe Gen 4×4 SSD, so by the end of the video you should know everything about M.2 drives like this! Let me start with the form factor. Drives like this are called “2280”, because they are 22 mm wide, and 80 mm long – pretty simple! You can get longer, up to 110 mm, and shorter, down to 30 mm, although this 2280 size is by far the most common. This drive will happily fit in anything from a laptop, to a desktop, to even a PS5!

On the end of the drive is the M.2 connector – there are a few different styles here, although this “M-Key” style on the NM760 is by far the most common these days. This allows for 4 PCIe lanes, plus power, to the drive at whatever PCIe generation the drive supports, which for the NM760 is the blazing fast PCIe Gen 4 standard. If we gently pull back the sticker you’ll see the first component, the controller. This is what the PCIe bus connects to, and what handles all the data being sent to be stored. In this case, Lexar is using the Silicon Motion SM2269XTF, one of their newest NVMe 1.4 compatible controllers built using the energy efficient 12nm process meaning less heat and longer battery life on portable devices like laptops. If you have the space you can even use an optional heatsink to get even lower temperatures, and even more stable performance.

The controller’s job is to be the middleman between your system, via the PCIe bus, and the flash storage we’ll cover in a second. One of the controller’s main tasks is to map out where it stores each piece of data in the actual memory chips – you can think of the flash as the shelves in a massive warehouse and the controller notes down where it stores each item, so whenever you need to access it again it can look up on it’s list then go fetch what you’re after. That list is generally stored in one of three places: on the flash itself; in a DRAM cache; or in system memory. A DRAM cache is generally the fastest – something Lexar’s Professional Series NM800 features – although to help reduce the cost and make a drive like the NM760 as affordable as possible you can omit the DRAM chip and instead either store the list in a fixed space on the flash, or even better and just use the system’s memory instead using a technology called “Host Memory Buffer”. This is great, as while a DRAM cache is going to be faster, it still offers an insane 5.3GB/s in reads and 4.5GB/s in writes, plenty for anything from gaming to content creation.

While there is more the controller does I’d like to explain, it’s worth knowing some background on the flash chips that actually store the data. You’ll often hear them called “NAND Flash”, because they are made up of “NAND” or “Not-AND” gates. We don’t need to go into the weeds with that, in short let’s say that you have a row of cells that can store data. In the NM760, it uses TLC or Three-Level-Cell flash so it can store three bits per cell. Each of these chips can store 512GB of data, meaning there is something like 170 billion cells per chip – that’s insane!

You can equally get more or less bits per cell – TLC or three bit is the most common, but QLC or quad bit, MLC or two bit, and even SLC or single bit options are available. The more bits the more data-dense the chips can be, often at the cost of performance and endurance. One of the tricks the controller can do to eek out some extra performance is basically pretend that the TLC flash it’s connected to is actually SLC or single bit. It’s faster to write to a single bit in each cell than it is to write to all three bits at once, so the controller will essentially spread the data out, then once the transfer is complete it can then shuffle it all back into an easier to read format.

Thanks to the TLC flash, the density of each of these chips is frankly insane – this being the 1TB model it has just two of these chips onboard, both from longsys, Lexar’s new parent company. These are actually 3D TLC chips, meaning the cells are layered too for much better density. What’s also impressive is their endurance – basically how much data you can write to them before they are likely to fail. This 1TB NM760 drive has a PETABYTE written rating – as in you can write a petabyte of data to it and Lexar doesn’t think you’ll have a problem. A petabyte! They expect you can fill the drive, then empty it, then refill it a thousand times. That’s incredible.

And that’s pretty much it – you have three main types of chips on an SSD, the controller, optional DRAM cache, and the NAND flash. It’s worth noting that only the controller generally needs to be cooled – the NAND flash actually prefers to be warmer for the best performance – so keep that in mind if you are using a heatsink. Thank you to Lexar for sponsoring this video, and thank you to you guys for watching. If you want to check out the Lexar NM760 and maybe pick one up yourself, head to the link in the description below!