Solid state drives or SSDs are based on the use of non-volatile RAM. And therefore, like a hard drive, they can store data that remains in memory even after turning off the computer. However, their advantage is that they do not rely on a head and disk to access the data. They do it in the same way as conventional RAM. This allows them to access multiple data at the same time and do it in less time by not having to reposition the plate and stylus. In addition, it brings with it the advantages of using an electrical interface for direct data transfer. As is the case with PCI Express 5.0 SSDs.
What does PCI Express 5.0 bring to NVMe SSDs?
The fifth generation PCI Express connection can transmit up to 4 GB/s of data in parallel per data pin. This means that solid-state drives of the M.2 type that use a variant of the standard with 4 lanes can transmit up to 16 GB/s of data. However, this must be qualified and made clear from the outset that drives intended for PCIe 4.0 or below will not get an automatic increase in bandwidth.
This is because data access is managed by the flash controller, which performs the requests made by the processor to the SSD at a specific speed. Nor can we forget that for real effects it is not possible to use 100% of the speed either. This is because there are certain requests that take longer than the rest and, therefore, end up adding access time in total. So if logically we add time when making a data transfer, then the bandwidth is reduced.
That is why the first NVMe PCIe Gen 5 SSDs promise vtransfer speeds between 12 and 13 GB/s despite 16 GB/s. On the other hand, we haven’t seen any DRAM-Less drives yet. Which do not have RAM for the flash controller, which ends up affecting the total bandwidth.
Compute Express Link Compatible Drives
When we have two different memory wells, for example RAM and SSD. There has to be a mechanism for transferring the data. This is done via direct memory access drive or DMA. Its operation is as follows:
- They read data into source memory from the first DMA unit.
- They transmit the data to a second DMA unit on a secondary and independent memory channel.
- Data is transmitted from the second DMA unit to the destination memory.
NVMe SSDs in PCs use the PCI Express data path to copy data from RAM to solid state drive and vice versa. This opens up new possibilities such as the fact that graphics cards have direct access to information. Although that is already something that can be done with units under PCI Express 3.0 and 4.0.
It must be taken into account that one reason why software does not make good use of the capabilities of the SSD is due to the fact that data transfers have to be explicit in the program code. Well, the idea of the Compute Express Link or CXL is to provide unified access between the system’s RAM and PCI Express devices. So the processor sees everything as a single homogeneous block of memory. Thus automating the process of accessing and copying from one data to another and giving all applications the power of an NVMe SSD without code changes.
Drive design changes for PCI Express 5.0 SSDs
Well yes, and it is that until now we had different sizes of SSD drives, but with the same width of 22 millimeters. So we had units ranging from 22 x 110mm to 22 x 30mm. Instead, it seems that the third generation units will increase their width up to 25 mm.
This is a problem for designs that have just enough space for such a drive. However, if your PC only supports M.2 under PCI Express 4.0 or below. What advantage is having a PCIe 5 SSD if you can’t use its bandwidth? Actually, the extra 3mm of width will accommodate a larger heat sink. Let’s not forget that the higher the data transfer, the more heat it generates and that these units are usually in a closed space.
They will not be usable on PlayStation 5
The change in width means that they cannot be used on the PlayStation 5 console or any other type of drive that uses an M.2 type NVMe SSD with 22 mm width. In any case, it is not a loss since they do not have the capacity to take advantage of the high
Changes in terms of processor, graphics card and RAM memory
One of the things we’re going to see in the future will be drives with the ability to compress and decompress data at high speeds. Which will be key to freeing the processor from said task and allowing storage to be increased. At the moment, PC uses hardware technologies such as NVIDIA’s RTX IO and AMD Smart Access Storage through Microsoft’s DirectStorage API.
However, not everyone is going to have a high-end graphics card in their computer, and it won’t be long before we see drives that will provide virtually tens and even hundreds of extra gigabytes of storage. We will see these within future Intel Core and AMD Ryzen processors.
Because DirectStorage also allows direct access to the drive status to the graphics card. Well, they will also include this type of support units inside. After all, it is recommended that all the power of the graphics is focused on getting the best graphics at the highest possible frame rate.
