It is more than clear that the speed of SSDs with PCI Express interface is 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’re talking about an NVMe SSD there’s no discussion, but that’s not the case if we’re talking about SATA versus USB, especially due to the fact that SATA is stuck at 6 Gb/s for some time and in the case of USB we have already had 10, 20 and even 40 Gb/s interfaces for a long time. This is why internal units are gradually running out of steam in the market. However, if you are in doubt between an internal unit for one of your PC’s free bays or an external unit, 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 you are going to use, if you are going to connect to a USB 3.X type A then most likely you will be speed limited, since the most of these 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. Needless to remind you that using a 2.0 interface is already a waste of time and resources which will not bring you more performance than a classic external disk.
Is there a functional difference between the two types? No, not really, because internally they work the same way and differ only in the type of interface used to communicate with the PC. 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 left these types of solid units out of our comparison.
If you have an old laptop with a drive that you don’t use, we recommend that you adapt it to include an SSD drive in its bay. You’ll save desk space, the comfort of not having to carry the SSD on your back, and you’ll have a free USB port. Moreover, they are much cheaper. A Crucial X8, which is a 1TB USB-C SSD, can cost you around $170, while you can save $30 on one of the same brand and capacity, the MX500.
Does the interface affect SSD performance?
The transfer of information in an interface is always more complex than talking about maximum bandwidth, because we must remember that the efficiency of the memory controller is important. In the case of flash memory, it must be remembered that it is non-volatile RAM and its memory access is similar, but for this a flash controller is used, which will be the one who performs the access. At the moment this part is on the outside of 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.
Thus a flash controller that is not fast enough, for example of the DRAM-Less type, can be a much more relevant bottleneck than the communication interface. Let’s also not forget the SLC cache which, if filled, ends up causing a noticeable drop in performance.
In general, SATA and USB SSDs use the same components as Crucial’s MX500 and X8, so performance-wise they’re 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 in performance for the price.
