It is more than clear that the speed of SSDs with PCI Express interface are the fastest of all. However, not all computers can use fast NVMe drives and therefore only have access to drives with a SATA or USB interface. With laptops getting thinner and having eliminated space for 2.5-inch drives, the key question for many users is: is there a difference between an external and internal SSD?
The answer is that if we talk about an NVMe SSD there is no discussion, but it is not so if we talk about SATA compared to USB, especially due to the fact that SATA has been stuck at 6 Gb/s for some time and in the case of USB we have already long ago interfaces at 10, 20 and even 40 Gb/s. That is why the internal units are gradually losing steam in the market. However, if you have doubts between an internal unit for one of the free bays of your PC or an external one, you will be interested to know what the differences are.
Crucial MX500 vs X8, which is better?
Well, the answer is simple and it depends on the type of interface that you are going to use, if you are going to connect to a USB 3.X of type A, it is most likely that you will be limited in terms of speed, since most of those ports do not transmit more than 5 Gb/s of bandwidth. On the other hand, if the interface is USB-C you will get double the bandwidth. We don’t need to remind you that using a 2.0 interface is already a waste of time and resources that won’t give you more performance than a conventional external drive.
Is there any difference in operation between both types? No, not really, since internally they work the same and only differ in the type of interface used to communicate with the PC. Both SATA and USB, and unlike PCI Express, require access to RAM through the IOMMU placed on the motherboard chipset, while PCIe has direct access. So the communication latency is much lower in NVMe PCIe. However, we must not forget that we have left these types of solid units out of our comparison.
If you have an old laptop with a reader that you don’t use, our advice is to adapt it to fit a solid state drive in its bay. You will gain space on the desktop, the comfort of not having to carry the SSD on your back and you will have a free USB port. Plus they are much cheaper. A Crucial X8, which is a 1 TB USB-C SSD, can cost you approximately 170 euros, while you can save 30 euros on one of the same brand and same capacity, the MX500.
Does the interface affect the performance of the solid state drive?
The transfer of information in an interface is always more complex than talking about maximum bandwidth, since we have to remember that the efficiency of the memory controller is important. In the case of flash memory, we must remember that this is non-volatile RAM and its access to memory is similar, but for this a flash controller is used, which will be the one that performs the access. At the moment that piece is outside the processor, but we are very clear that it will not take long to see it integrated inside as it happened with the RAM controller, although for the moment the situation is different.
So a flash controller that is not fast enough, for example one of the DRAM-Less type, can be a much more relevant bottleneck than the communication interface. Nor can we forget the SLC Cache, which if it is filled ends up causing a noticeable drop in performance.
In general, SATA and USB SSDs use the same components as is the case with Crucial’s MX500 and X8, so in performance they are exactly the same. When is the portable unit better? When we don’t have a 2.5-inch bay available in our computer or need a totally portable drive, the SATA drive is superior when it comes to performance for the price.