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What is PCIe SSD?
A PCIe SSD or Peripheral Component Interconnect Express Solid State Drive, refers to a high speed expansion card that uses flash memory like other SSDs to store apps and files.
PCIe SSDs access the PCI Express slot of the computer and do not use the SATA chipset interface of the motherboard to communicate. These SSDs come with their own in-built storage controller that uses a driver unlike standard SSDs.
KEY TAKEAWAYS
- The PCI Express SSDs come in different versions and usually have 4 to 8 lanes but have the potential to perform much better than a traditional SATA or SAS SSD.
- The PCIe SSDs can be used as an alternative to server and enterprise-side flash employment and offer a much faster performance due to their low latency.
- Using PCI Express SSDs will not require sharing the bus because the flash is directly integrated on the PCIe interfaces and server motherboard and use their own serial link to connect to the host.
- PCIe SSDs offer faster loading of games and normal files, faster completion of intensive tasks, a lower boot time and a higher data transfer rate.
- Ensuring end-to-end data protection minimum latency and higher throughput, reduced cost of ownership, lower carbon footprints and production costs are some serious challenges faced in making the PCI Express SSDs.
Understanding PCIe SSD
PCIe SSDs are a high-performance storage solution that offers faster data transfer speeds and lower latency than traditional hard drives or SATA-based SSDs.
When choosing a PCIe SSD, it’s essential to consider the number of PCIe lanes used by the SSD and the available PCIe lanes on your motherboard.
PCIe (Peripheral Component Interconnect Express) SSD (Solid State Drive) is a type of storage device that uses the PCIe interface to connect to a computer’s motherboard.
PCIe SSDs offer faster data transfer speeds and lower latency than traditional hard drives or SATA-based SSDs, making them an excellent choice for high-performance computing applications.
PCIe SSDs use NAND flash memory to store data, just like SATA-based SSDs.
However, instead of using the SATA interface to communicate with the motherboard, they use PCIe lanes.
The number of PCIe lanes used by a PCIe SSD determines its maximum bandwidth.
One of the most significant advantages of PCIe SSDs is their high speed.
They can offer read and write speeds of up to several gigabytes per second, depending on the number of PCIe lanes used.
This makes them an excellent choice for demanding applications such as video editing, gaming, and virtual reality.
PCIe SSDs also offer lower latency than SATA-based SSDs because they bypass the SATA controller and connect directly to the CPU via PCIe.
This reduces the number of steps data must take to travel between the SSD and the CPU, resulting in faster access times.
When choosing a PCIe SSD, it’s essential to consider the number of PCIe lanes used by the SSD and the available PCIe lanes on your motherboard.
PCIe SSDs come in various form factors, including M.2, U.2, and PCIe add-in cards.
M.2 SSDs are the most common form factor and can be used in laptops and desktops with M.2 slots.
U.2 SSDs are larger and require a U.2 connector on the motherboard.
PCIe add-in cards are the largest form factor and offer the most PCIe lanes, making them an excellent choice for high-performance computing applications.
Uses
The PCIe SSDs are typically used by those people who want fast performance and a very low latency.
The PCIe SSD storage acts as a substitute to a server-side flash deployment.
This means that it is good to use the PCI Express SDDs in enterprise and server applications.
It is the PCIe interface that performs as the underlying layer for data transport typically on add-in cards and graphics cards.
It also allows connecting different devices.
Benefits
A few of the prime benefits of the PCIe SSDs is that these unconventional server-based high performing drives offer higher speed, better compatibility, and larger storage capacity.
Also, the PCIe SSDs eliminate the need to share a bus since they integrate flash directly on a PCIe interface and a server motherboard.
This helps in connecting to the host via their own serial link.
Then there is the point-to-point architecture of the PCIe SSDs that improves the data transfer speeds and reduces latency between the storage and a server.
All these enable the PCIe SSDs to perform much better in comparison to a SATA, a SAS SCSI or Serial Attached SCSI, and Fiber Channel SSDs.
This is primarily because the PCIe SSDs take the functioning of the SSDs a step further by using the highest bandwidth channels in the computer which offers amazingly fast speeds.
And, with the advent of the 12th Generation Alder Lake Systems of Intel, there are new generations of such storage systems such as PCIe 3 SSD, PCIe 4 SSD, and PCIe 5 SSD.
The benefits offered by these PCIe SSDs are:
- Near-instant loading of normal files
- Fast completion of disk-heavy tasks usually within a minute or two if not in a few seconds
- Faster loading of games
- A much higher data transfer rate and
- A much lower boot time which is often limited to a couple of seconds.
If the PCIe SSD belongs to the latest version then you will also have a much higher bandwidth because the amount of bandwidth available in each PCI Express lane roughly doubles in each version.
This will translate into faster storing and loading speeds of games and videos and faster graphics rendering for high resolution videos and modern games.
However, everything is not good for the PCIe SSDs. These are quite expensive and maybe all motherboards may not support it.
Add to that, another drawback is the absence of regular storage commands which needs the manufacturers to create a custom software driver for the operating system.
Also, power consumption is an issue for CPU or RAM intensive tasks.
Still, the latest versions of the PCI Express SSDs are good to use in a computer and make it future proof.
Challenges
There are quite a few challenges faced by the manufacturers of the PCIe SSDs which, when overcome, will make these devices more popular in the future.
One of the most significant challenges is creating an inherent end-to-end data protection aptitude in these systems that will be clear to the end users.
Also, it is required to ensure that such a system offers a minimum impact on the latency and throughput.
Another significant challenge is ensuring a less significant carbon footprint as well as a reduced total cost of ownership.
That is not all. The manufacturers also need to find ways to reduce the production costs to make the PCIe SSDs much more affordable to the users and look seriously into the time to market without compromising with the interface homogeny.
It is also found that even after the launch of the 12th generation Alder Lake processors of Intel, the PCI Express SSDs lag behind in taking the fullest advantage of it.
Since pushing large amounts of data at high speed involves high power consumption, maintaining a safe operating temperature is another significant challenge.
This, along with the area and system latency challenges, are the key parameters of concern for the manufacturers which forces them to reconsider, if not re-architect the design.
However, the design itself is creating a lot of challenges down the road since it is getting more complex than before to add more features and functionalities, of which the most important is security.
Add to the design and size, the timing complexity is also increasing the challenges for the manufacturers.
Single stack or single row/single column orientation or multi-link bifurcation with double stack orientation may help in the performance of the systems but that needs exhaustive knowledge and tools to implement, adding to the challenges.
Then there is the typical challenge of overcoming the performance issues that arise from the lack of careful coordination between the host interface and the flash interface.
Some amount of parallelism is required to achieve the desired performance level. Multiple dice should be programmed so that they return the results at once.
Also, specific techniques such as native command queuing, block picking, and garbage collection must also be balanced in order to achieve a high performance through parallelism.
However, at the same time it should be kept in mind that the power envelope of the SSD is not exceeded.
The flash cells hold some amount of voltage which may get altered when the controller makes a request for the voltage from the cell when it is read too many times.
This is called read disturb management and this needs to be monitored and managed so as to determine the number of times a cell can be feasibly and effectively read.
When it is found that a particular cell has been read too many times, the data in that specific cell can be transferred to another cell which will start the cycle clock counter from the beginning.
However, it is quite a difficult challenge to know when and how to move the data from one cell to another when the read times surpass the preset threshold.
This is because if too little data is moved, you may end up losing data and if you move data every now and then more than that is necessary it will add to write amplifications and reduce the performance level.
Apart from that, temperature management is another challenge. If this is not controlled properly and timely, the controller or the flash memory will become too hot and may even burn out too early.
It is therefore needed to understand the behavior and temperature of the whole drive to mitigate the impact.
Writing seems to draw the most power and heat things up excessively and quickly.
Once again, the controller needs to monitor the temperature and slow things down and control the power consumption, especially writing, to ensure that the temperature level does not cross the preset threshold.
Here lies the challenge. Ideally, it is pretty difficult to regulate the write speeds of the drives without immobilizing writing on the whole.
In order to ensure that the writing activity does not stop entirely, the controller needs to take into account several different temperature thresholds and constrict the writing performance.
Designing a proper firmware for endurance is another significant challenge but it is extremely necessary to ensure that the controller is able to write but there is no write amplification. This will help the drives last longer.
Apart from that, life curve throttling should also be used in order to augment the write performance.
This particular technique involves tracking the amount of data that needs to be written in a particular time period.
This is typically done by the debits and credits system.
If it is found that the drive has accumulated a lot of debits, so much that the life span of the drive is threatened, it will automatically slow down the drive.
After this process is completed successfully, the write performance will be throttled back just as required.
However, the problem here is that most fundamental SSD controllers are typically not compatible with this process of live curve throttling.
These controllers of the drive simply restrict the total amount of writes sent to it over its lifespan.
And, this is very difficult, if not impossible, to track it manually and restrict the traffic to the drive.
In order to maintain a consistent performance level, the flash vendors however are contemplating on the erase part of the cycle.
Add to that, adding newer and better flash managing features will also optimize the performance.
Perhaps, one of the best ways to improve the performance is to incorporate data protection and data integrity routines.
When these challenges are overcome, you can expect to see more and more users choosing better and more reliable storage options in the form of PCI Express 5.0, 6.0, and NVMe based Solid State Drives.
Conclusion
Coming to the end of this article, now you surely know how useful the PCI Express Solid State Drives are.
Though there are a few specific challenges to overcome by the manufacturers, these alternative storage options provide a lot of benefits to the users.