Is there a thing called external RAM? Is it possible to add an external RAM for laptop? If you are wondering these problems, you can read this post, in which MiniTool shows you why the external RAM is impossible now.
Nowadays, we have external hard drive and external GPU. Some people may wonder whether it is possible to have external RAM for laptop. To figure out this problem, we should first know how the external hard drive or external GPU is added to the laptop.
How Is an External Hard Drive Added to Laptop?
In general, the laptop will come with one or more external ports like USB ports, Thunderbolt (PCI-E) ports, etc. These ports can be used to connect external hard drive.
To connect an external hard drive to a laptop, you just need a cable. One of the reasons is the USB PD (Power Delivery) Protocol. This protocol is one of the current mainstream fast charging protocols.
It can increase power transmission through USB cables and connectors to expand the power supply capability of the USB cable bus. The power delivered can reach up to 100W. With this protocol, you can use the USB or Thunderbolt ports to supply power to the external hard drive.
However, there is no such a power delivery protocol that can supply enough power to external RAM. After all, RAM's speed is much higher than hard drive's, and therefore it will consume more power.
How Is an External GPU Added to Laptop?
Some people may ask why not to add the external RAM to laptop like an external GPU. In this way, we don't need to worry about the power delivery issue. Then, let's see how an external GPU is added to a laptop.
To connect an external GPU, you need an external GPU expansion chassis with a built-in PCI-E slot, a power supply, and a cooling system. Of course, this device requires a Thunderbolt port on the laptop.
This post explains to you what a Thunderbolt hard drive is and recommends 3 best Thunderbolt external hard drives to you.
If all the above things are prepared, you just need to insert a discrete GPU into the eGPU device, connect the eGPU device to the laptop via a Thunderbolt port, and then plug in the power supply. In this way, you can enjoy the performance improvement brought by the eGPU.
However, you should note that GPU usually uses PCI-E x8 or PCI-E x16 bus, while Thunderbolt 3 port uses PCI-E x4 bus. That means Thunderbolt interface will limit the performance of the external GPU.
This post tells you the differences between PCI and PCIe. It also shows you how to distinguish them.
Why Is the External RAM for Laptop Impossible Now?
According to the above content, we can know that the external RAM for laptop is impossible now for the following reasons:
1. No Power Delivery Method
There is no method that can be used to deliver power supply to external RAM, except that you use a chassis like eGPU box. This is very inconvenient.
2. No Suitable External Port
As we all know, nowadays, common external ports include USB port and Thunderbolt port. However, RAM should use DDR, DDR2, DDR3, or DDR4 interface. These interfaces are incompatible with USB or Thunderbolt port.
Besides, although the data transfer speed of USB 3.0 can be up to 5Gbps (about 600MB/s), and Thunderbolt 3 interface's speed can be up to 40Gbps (5GB/s), these speeds can't match that of RAM.
Nowadays, we usually use DDR3 or DDR4 RAM. However, some DDR3 RAM can be up to about 15 GB/s and some DDR4 RAM can be up to 25 GB/s. At present, there is no external port reaching these speeds.
Of course, some people also think that external RAM is unnecessary, because the RAM in laptop is usually replaceable. If you are not satisfied with the RAM, you can replace it with a better one.