PCIe vs SATA: Which SSD Interface You Should Choose?

Last Updated: May 29, 2017

Solid State Drives have improved a lot over the past few years. What used to be expensive to most of us five years ago, is now much more affordable. At present though, there’s a lot of confusion surrounding the different types of SSDs and the interfaces available. Nearly any SSD will give you noticeable performance difference over a mechanical hard drive. SATA, NVMe, M.2 based SSDs are the popular ones available right now, and people are not sure of which one’s right for them or which one performs the best. This is exactly why we’ve decided to discuss about it today. Well, without further ado, let’s pit the two primary interfaces that SSDs today are available in – SATA and PCI Express.

SATA vs PCIe

Serial ATA and Peripheral Component Interconnect Express are the interfaces that are widely used by SSDs that are available today in the market. There are a lot of key differences between these two interfaces that can create a lot of confusion among the consumers. So, let’s take a look at these differences:

1. 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.

2. 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.

SATA SSD speeds

3. SATA III SSDs

SATA III SSDs are usually available in a 2.5 inch form factor, which utilizes SATA cables to connect to the motherboard. As a result of indirect connection using cables, this might result in high latency which can affect the maximum potential of the SSD.

M.2 is a new form factor slot on the motherboard to allow the installation of smaller SSDs in compact devices like laptops. Nowadays, this slot has made its way to several ATX, Micro-ATX and Mini-ITX motherboards which are used on desktops as well. There’s a lot of confusion surrounding M.2 SSDs among consumers. Make no mistake, M.2 slots on the motherboard can have SATA and PCIe lanes going to the slot. This, totally depends on the motherboard you’re having. You will have to dig into the specifications to make sure of that.

Samsung 850 EVO SSD for example, can be bought in either 2.5 inch or M.2 form factor. Both of these SSDs, regardless of which form factor you’re going for, max out at SATA III speeds that’s usually 600 MB/s.

4. PCIe SSDs

Non-Volatile Memory Express (NVMe) is a rapidly developing communication protocol that allows an SSD to make effective use of a high speed PCIe bus in a computer. PCIe is the same interface that’s used by graphics cards, sound cards and Thunderbolt. PCIe 3.0 offers almost 1 GB/s per lane. If you put a card in a four-lane slot, you’ll basically get 4 times the bandwidth, at nearly 4 GB/s. Now this is insanely fast, even if you compare it against SATA based SSDs. NVMe is in fact, considered as a replacement to the AHCI protocol, used by most SATA based SSDs today. You can take a look at the performance of my Samsung NVMe SSD which I currently have on my Alienware 15 R3 laptop below.

PCIe SSD speeds

Now, on the other hand, the M.2 slots that we discussed earlier, can have PCIe lanes going to the slot. So, the PCIe based M.2 SSDs makes use of the NVMe protocol for blistering fast speeds, easily managing speeds upwards of 2000 MB/s. Currently, the world’s fastest consumer SSD is the Samsung 960 Pro NVMe M.2 SSD which can provide sequential read speeds of nearly 3500 MB/s. This is a huge step-up from the 550 MB/s offered by high-end SATA III SSDs. The NVMe protocol will only get better in the future, so if you want the absolute best speeds, PCIe based SSDs are the ones you should be looking at.

Apart from this, Intel has been working hard on a newer and much faster SSD called the Intel Optane Memory, based on their own 3D Xpoint technology. Although Optane is based on PCI Express, Intel claims the Optane is 4.42 times faster than a NAND based NVMe SSD in terms of I/O operations per second. They also promise 6.44 times lesser latency in Optane. Although you cannot buy it at the moment, it’s under development and is expected to be available by the end of next year. So, from this we can be sure of the fact that, PCIe based SSDs are the future.

5. 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.

PCIe vs SATA: Which SSD Interface Should You Go For?

Now you know the differences between all the types of SSDs that are available on the market toda, you should definitely have a better idea as to which one to buy. If you ask me, I would say that it totally depends on your needs. If you’re on a budget and want decent SSD storage, a SATA based SSD would do just fine. However, if you’re looking forward to future-proof your system, then a PCIe based NVMe SSD is the one you should be going for.

                SEE ALSO: SSD vs. HDD: Which One Is Better, And Why?

Upgrading to an SSD?

Well, those were the differences between the two popular SSD interfaces, PCIe and SSD. I hope you can make the choice easily now. So, are you going to upgrade to an SSD in the near future? If so, let us know which one you’re going for, a SATA-based SSD or a PCIe-based SSD. Let us know your thoughts and the one you are going for in the comments section below. Also, if you’d like to see more such articles, do drop us a line and we will make sure to consider it.

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The guy who settles for nothing less than the absolute latest and greatest in technology. A sucker for anything hardware related and prefers iOS to Android. Because, reasons. Also, I spend the other half of the day playing Battlefield with gamers from around the world. That's right, all hail the glorious PC Master Race.

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