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 v3 only offers a max of only 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 rate. It’s used by high-speed devices that generate a lot of data 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 interfaces through which you add components to your PC 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.
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 0.750 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 that these numbers are the theoretical maximum speeds of the standard. The connected device often do not saturate even this.
Connected devices often operate at much lower speeds than theoretical max speeds. For instance, a SATA 3 SSD operates at a nominal speed of about 0.560 GB/s NOT 0.750 GB/s
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 eight 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 for optical drives.
It serves as the main interface for three popular devices for both laptops and desktops:
1. Hard Disk Drives
Perhaps the most important use of the SATA port is that it connects hard disk drives (HDD).
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 750 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 they are relatively cheaper than NVMe SSDs and 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 required 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 only 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 750MB/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 so that it improves its speed with each new version. Like SATA with each new iteration, the PCIe interface doubles its speed per lane.
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!
A typical PC has about 20-24 PCIe lanes available for your to put devices into.
Also Read: How Many PCIe Lanes Do I Have?
What is PCIe Used For?
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. These require a single lane.
- 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. Each NVMe SSD requires 4 x PCIe lanes to perform optimally
- 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 in terms of which is faster. 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 either 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.