A head-to-head speed comparison will indicate that PCIe is the obvious winner. With the current trending PCIe generation v4.0, you can get throughout rate (speed) of about 2 GB/s on an x1 slot and about 32 GB/s on an x16 slot. In comparison to this, the current SATA 3 only offers a max of 0.75 GB/s (6 Gigabits per second).
However, the intended purpose of the two standards is quite different. The PCIe standard offers high-speed transmission lanes with large data throughput. It’s used by high-speed devices for this reason.
On the other hand, SATA interface is used for devices that have a low bandwidth requirement such as Hard Disk Drives, SATA SSDs and CD Drives.
So the simple answer to the question, which is faster PCIe or SATA, is PCIe obviously. However, both standards are the fundamental interface through which you add components to your system and depending upon what you intent to build, one interface may be more important than the other.
For instance, if you are building a gaming PC or a simulation workstation, then PCIe slots that can house high speed devices would be instrumental. On the other hand, if you are building a NAS system, you may find the availability of a high number of SATA ports more important.
So Which Is Faster PCIe or SATA?
As mentioned earlier, if you are talking about raw speeds, then there is literally no comparison between PCIe and SATA. PCIe is multiple folds faster than the SATA interface.
Let us do a simple comparison here.
Image: Different versions of SATA ports are color coded (often different versions are found on older boards)
The following are the speeds of the SATA interface, the current generation of SATA is 3.
- SATA 1: 1.5 Gbps or 0.1875 GB/s
- SATA 2: 3.0 Gbps or 0.375 GB/s
- SATA 3: 6.0 Gbps or 0.700 GB/s
Two things to note here. First, Gigabits per second (aka Gbps or Gb/s) is NOT the same as Giga Bytes per second (aka GB/s). There are 8 bits in a byte.
The other thing to note is these are theoretical maximum speed of the standard. The connected device often do not saturate even this.
Image: There are various sizes and types of PCIe slots.
The speed of a PCIe slot depends upon how many PCIe lanes it has and what its version is. There are four types of PCIe slots:
- x1: has a single PCIe lane
- x4: has four PCIe lanes
- x8: has 8 PCIe lanes
- x16: Largest and has 16 PCIe lanes.
The following table summarizes the PCIe speeds for different version and lane count. Note that the most current generation that has picked up steam in the market is V4.0. V5.0 and V6.0 are currently not available.
Hence you can see here that even the smallest x1 slot with a single PCIe lanes on version 3.0 and v4.0 standards is faster than SATA 3 interface. However, as mentioned earlier, they both serve different purposes.
What is SATA and What is it Used For?
Serial ATA (SATA) is a standard that has been around for decades now and is very commonly used for mass storage devices as well as optical drives.
It serves as the main interface for three popular devices for both laptops and desktops:
1. Hard Disk Drives
Image: spinning hard disk drives are perhaps the most important component that interface with SATA ports.
Perhaps the most important use of the SATA port is that it connects with hard disk drives.
The spinning hard disk drives that is found in almost all computers use the SATA 3 interface.
A good 7200 RPM hard disk drive has a max transfer speed of about 200 MB/s. Hence, the SATA 3 interface with its 700 MB/s transfer speed cap is more than sufficient for even the best spinning hard drives!
2. SATA SSDs
Another storage device that SATA interface connects to is SSDs – but only a particular type of SSD.
SATA SSDs are much slower than the NVMe SSDs – the latter use the PCIe interface.
The benefit of SATA SSDs is that not only are they cheaper, they are also much easier to connect to your PC. To explain this further, a PC has a plethora of SATA ports that you can connect a SATA SSD to, but only a very limited amount of M.2 slot for PCIe NVMe SSDs.
A SATA 3 SSD has a max transfer speed of about 560 MB/s, hence it is easily 2-3 times faster than an average hard disk drive.
However, compared to a PCIe SSD, it is no way close. A v3.0 PCIe SSD can reach speeds of upto 3500 MB/s (Samsung 970 EVO). A V4.0 PCIe SSD can reach speeds of upto 7000 MB/s (Samsung 980 Pro)!
Again, PCIe SSDs require specialized M.2 slots and most PCs come with one or two slots.
3. CD/DVD/Blu Ray Drives
CD/DVD drives, aka optical drives, also use the SATA interface for connectivity.
CD and DVD drives are notoriously slow with the fast 24x DVD drives having speeds of 32 MB/s and the fastest 16x Blu Ray Drives having a data rate of 72 MB/s.
Hence, they are far slower than the maximum data rate cap of the SATA 3 interface i.e 700 MB/s
- Does it Matter Which SATA Port You Use?
- How Many SATA Ports Do I Have?
- How to Add More SATA Ports to Motherboard?
What is PCIe and What is it Used For?
Peripheral Component Interconnect Express (PCIe) uses PCIe lanes to offer a high-speed connection between the cards installed in PCIe slots and the chipset.
The technology, much like SATA, has been developed and with each new iteration, the PCIe interface doubles its speed.
Aside from that, each version also has different slot configurations depending on the number of lanes associated with the slot. These are X1, X4, X8, and X16 which have 1, 4, 8, and 16 lanes respectively.
It is crucial to highlight here that the amount of PCIe lanes a system has are limited and thus you cannot connect an unlimited amount of devices to your PC!
Also Read: How Many PCIe Lanes Do I Have?
What is PCIe Used For?
Image: WiFi Expansion Card goes into PCIe x1 slot.
PCIe is used for connecting a variety of high speed devices also known as expansion cards. Depending upon the bandwidth requirement of the expansion card, you use different slot sizes.
Here are some of the expansion cards that get attached to PCIe slots
- Graphics Cards: Very popular among gamers, professionals and enthusiast and also the most demanding. Uses 16 lanes ideally.
- Sound Cards Most motherboards come with a built in sound card but dedicated sound cards are excellent for audiophiles
- Network Card: These can add Ethernet, WiFi and Bluetooth functionality
- SSD Expansion: If you want to add more PCIe NVMe SSD, you can get and SSD Expansion card
- Port Expansion: For adding more SATA or USB ports
- Video Capture Cards: These cards are used to capture raw video data and turn it into digital data that can be then edited.
- TV Tuner Card: For turning your PC into a TV
PCIe is clearly the winner here by a long shot. However, as mentioned earlier, PCIe and SATA serve different purposes.
The devices that attach to these interfaces are also different and not cross-compatible. Therefore, the question, which is faster PCIe or SATA, is not relevant since a particular device does not give you a choice to install it in PCIe or SATA slot.
Another important point to note is that every device has a data rate limit due to its mechanical or electronic design. For instance, if a hard disk is designed to achieve a max transfer speed of 200 MB/s due to its mechanical design, it will not benefit if you were to somehow install it on a PCIe slot.