SSD aka Solid State Drive is one type of storage device that can work by replacing the hardware. It is like the replacement of the hardware of a computer. The interconnected flash memory chips are the main parts SSD uses to store data. It’s use makes one’s computing reliable and faster at the same time. These memory chips are on the small box circuit of the SSD. Even though the primary purpose of all SSD is to keep memories, they are all different considering their features. Its SATA connection, PCIe slot connection, speed, or M.2 connector as well. These things make an SSD different from another one.
There has been a new term Class that Dell has come up with. At first, the users didn’t know what this class indicates and what is the difference between each class. Such as Class 10, Class 20, Class 35, or Class 40. What makes them different and which one is better than the other? These questions have continuously aroused people. Now let’s dig into it and see which one is better between SSD class 35 and SSD class 40.
What does SSD Class mean?
Class is one type of grading system that the Dell company first came up with. Since SSDs performance differentiation can be difficult sometimes when adding the firmware or the controller, this grading system is like a savior.
Class means to rate the speed of the disk. The higher you go, the faster it will be. Moreover, the interface also improves by getting a higher class.
| Class | Connector | Marketing | Sequential Read/Write | Random Read/Write | Interface |
| 10 | SATA | Value | 520 MBps/320 MBps | 30 MBps/10 MBps | SATA [Dram-less] |
| 20 | SATA | Mainstream | 500 MBps/300 MBps | 80 MBps/60 MBps | SATA |
| 30 | SATA | Performance | 550 MBps/350 MBps | 90 MBps/75 MBps | High-performing SATA |
| 35 | PCIe | Performance | 800 MBps/1200 MBps | 95 MBps/- | NVMe [Dram-less] |
| 40 | PCIe | Performance | 1500 MBps/ 350 MBps | 200 MBps/80 MBps | NVMe PCIe |
The higher the number of Classes is, the more reliable and fast it is. That’s why when comparing, the higher SSD classes become superior.
Class 35 SSD vs Class 40 SSD
If we see the main grading system Class defines, SSD 40 is faster and better. Class 35 uses a single module or NAND flash memory. Since NAND, multiple layers do not require power or other means to store data, it is convenient and has better means. It uses NVMe but that is DRAM-less. To replace DRAM, class 35 SSD offers HMB. HMB stands for Host memory buffer. Its sequential read is 800 MBps and its write is 1200 MBps. The random read is somewhat near 95 MBps.
On other hand, Class 40 has multiple NAND modules. The more module an SSD has, the faster it works. That’s why class 40 has a fast speed and better storage performance. The NVMe PCIe interface it features has DRAM. Its sequential read and write are respectively 1500 and 350 MBps. The random read and write are 200 MBps & 80 MBps.
While comparing the module, speed, readings, and interfaces, Class 40 SSD is better than 35. That does not mean Class 35 is not on par. Just a few differences made it happen. However, Class 35 is cheaper and offers faster performance, though not as much as 40 class SSD.
