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SATA SSD and PCI-E SSD, how to choose?
Our pursuit of SSD speed is getting higher and higher, and main factors affecting read and write speed of SSDs are data channels, PCI-E and SATA, so what are characteristics of SSDs with PCI-E channels and channels? SATA - what's difference? Which one is better or worse?
What are advantages of a PCI-E channel
When SATA channel reads and writes data, data must pass through memory and then reach CPU or HDD, while PCI-E channel directly connects CPU and HDD through bus, keeping memory node. , so there is no delay in transmission, natural reading and writing speed is faster, and data volume is also larger.
The actual read/write speed of SATA 3.0 basic SSD is 560MB/s, actual read/write speed of SATA 2.0 is about half that of SATA 3.0, and actual read/write speed of PCI-E 2.0 is up to 780MB/s~ 1560MB/s, PCI-E3.0 is twice as fast as PCI-E 2.0, and speed is quite fast.
Some people think that M.2 SSDs are PCI-E channels, but they are not. M.2 SSDs also have SATA channels. In addition, even solid-state drives using PCI-E channels can have different speeds on different motherboards, too. Because PCI-E channels of some motherboard manufacturers are native to CPU, and some are extended through PCH southbridge, which will affect read and write speed of the SSD.
AHCI and NVMe
The AHCI protocol and SATA link are specially designed for mechanical hard drives because latency of mechanical hard drives is relatively high. Of course, SSDs will also use AHCI protocol and SATA channels, but speed of this SSD-state drive is naturally not high. If you want to increase read and write speed of SSDs, AHCI protocol should not be suitable, so there is NVMe protocol for high-speed SSDs, and biggest advantage is low latency.
For SSDs, if NVMe protocol is used, its sketching performance must exceed SATA link limit. Therefore, an NVMe-enabled SSD typically has an M.2 interface and a PCI-E channel. All SATA SSDs cannot support NVMe protocol.
Here is a table that everyone can understand.
PCI-E has many advantages, but price is quite high. A 500G SATA SSD costs about 800 RMB, while a 500G PCI-E SSD costs about 2,000 RMB. In addition, not all motherboards are suitable for using PCI-E SSD, Some entry or mid-level platforms have very few CPU channels, so it is not suitable for using PCI-E solid state. If you want to use it, you must match it with a high-end motherboard.