PCIe (PCI Express) supersedes SATA as the latest high bandwidth interface. Entry level PCIe SSD speeds are two to three times faster than the older generation of SATA 3.0 SSDs mainly due to the number of channels contained by each to transfer data (roughly 10 for SATA and 25 for PCIe). However, depending on usage, real world benchmarks may not reflect this massive gain due to bottlenecks elsewhere in the PC. We leave it to your interpretation of thousand of real world benchmarks to assess whether the premium is justified for PCIe NVMe versus SATA SSDs
SATA is the market incumbent and dominant interface for connecting an SSD to the PC. It employs the command protocol AHCI (it also supports IDE) which was built with slower spinning disks in mind rather than flash memory. SATA transfer rates begin at 150 MB/s and max out at 600 MB/s for third generation technology. For most consumer uses of SSDs this is absolutely adequate.
- The Connection
Serial ATA (SATA) is the most widespread interface used for connecting SSDs today. This interface has been around for quite a long time now. Know the SATA cables that we use to connect our mechanical hard drives? That’s exactly the cable used for SATA based SSDs as well. SATA III, the most recent iteration of the interface has a maximum throughput of 6 Gbps which roughly equates to 600 MB/s in real-time performance. Because of their popularity and the number of manufacturers making SATA based drives, the SSDs based on SATA III interface are the lowest priced SSDs available in the market today. These SSDs are usually 2.5 inches and you can find it online for as low as $50.
The PCI Express interface is a high speed serial expansion card format that uses point-to-point architecture. This is the same interface that we all use to connect our Graphics cards. The PCIe based SSDs plug into an expansion slot on your motherboard, that provides both data and power connections. So what’s their role in SSDs you may ask? Unlike SATA based SSDs, PCIe can allow more bandwidth through faster signalling and multiple lanes. Due to the direct connection to peripherals, SSDs based on PCIe perform much better than the SATA counterparts that uses cables to connect to the motherboard, which in turn results in high latency. For example, the Samsung 960 Pro NVMe SSD boasts about 4-5 times the performance of SATA based Samsung 850 Pro.
- Performance
The performance gap between SATA and PCIe is quite huge, as SATA III maxes out at 6 Gbps or 600 MB/s. On the other hand, two lanes of PCI Express 3.0 can provide more than 3 times the performance of SATA III based SSD at nearly 2000 MB/s. All this while consuming just 4% more power than a SATA III SSD. This is clearly a win for PCIe Interface.
Even the cheapest PCIe based SSDs will offer significant performance gain over the SATA based SSDs and if you go for higher-end ones, the performance will only be much better. As of today, the SATA III interface is considered as a bottleneck for SSDs because it caps at approximately 550 MB/s in real world performance tests. If your demands are quite high and you want a higher performing SSD, you probably know which interface you should be going for, by now.
- Pricing
Now we know how much faster the PCIe based solid state hard drives are, compared to the ones based on SATA. But all of this performance gains comes at a cost. Although the prices of SATA III based SSDs have come down by a considerable margin. If you take a look at the fastest SATA based SSD you can buy, the Samsung 850 Pro costs approximately $1000 for the 2TB variant.
On the other hand, the newer and faster NVMe SSDs cost hundreds of dollars depending on the storage space you’ll need. For example, the world’s fastest Samsung 960 Pro SSD costs almost $1200 for the 2TB variant. That’s sky-high pricing for blazing fast speeds, especially considering the fact that most of our PCs and laptops costs under thousand bucks. But, if you still want to buy the best one out there, you can purchase it from the link below.
Which Type of SSD Is Right for You?
If you’re on a budget, go with SATA. If you want maximum performance that includes big file transfers, go with PCIe. Both are most convenient to use in the M.2 form factor, and both are demonstrably better than HDD in terms of speed, so you really can’t go wrong.
Note that there are several other SSD-related terms you should know, like TRIM and SLC/MLC/TLC. You should also keep up with good SSD maintenance and be wary of these signs that your SSD is about to fail.