”4K Performance”? Easy to see if your SSD is Good or Bad

Reading Guide: AS SSD will first continue to write to the tested partition in terms of the size of 16MB, generate a file that reaches the size of 1GB, then read the file with the same unit size, and finally calculate the average score and give the result.
The test file will be deleted immediately after the test.

01. Introduction

We often use AS SSD Benchmark when testing SSD.

Through this software, we can get some general information about the reading and writing of SSD.

However, some friends with high skills can judge the performance of SSD by the 4K reading and writing performance tested by this software.

Today we’re going to take a look at AS SSD Benchmark and the so-called “4K performance.”

AS SSD Benchmark is the software commonly used by many of us to measure the speed of SSD.
But many of us just look at the test data but do not understand the meaning of each test project, let alone the reading, writing, and application of SSD, which leads to some misunderstandings.

Let’s first take a look at the specific meaning of several test projects of AS SSD Benchmark.

• Seq (continuous read and write):
  AS SSD will continue to write to the tested partition in terms of the size of 16MB, generate a file that reaches the size of 1GB, then read the file with the same unit size, and finally calculate the average score and give the result. The test file will be deleted immediately after the test.

• 4K (4k single queue depth):
  random single queue depth test. The test software generates the 1GB size test file with a unit size of 512KB and then carries on the random 4KB unit size write and read test within its address range (LBA) until it runs through this range, and finally calculates the average score to give the result. Due to the generation steps, this test will generate a total of 2GB of data written to the hard disk, and the files will be temporarily retained after the test.

• 4K-64Thrd (4k 64 queue depth):
  random 64 queue depth test, the software will generate 64 16MB size test files (total 1GB), then write and read these 64 files in the unit size of 4KB at the same time, and finally take the average score as the result to generate the data write the amount of 2GB. The test file will be deleted immediately after the test is completed.

• Access time:
  that is, the data access time test, which reads the entire address range randomly with 4KB as the unit size, (LBA), with 512B as the write unit size, randomly writes within the reserved 1GB address range, and finally gives the test results with average scores.

• Score:
  something like your test score in school.

Most rookies look at the continuous reading and writing speed during the test.
The rookie with higher skills is to look at 4K and 4K-64Thrd here, looking at the so-called “4K performance” to judge whether SSD is good or bad.

02. What is 4K performance?

In SSD, 4K is the smallest read and write unit SSD. For example, if we need to write 2K of data, we actually have to write 4K; if we need to write 13K of data, we have to write 16K of data (write magnification is not considered here).

In view of this, the data we write is made up of countless 4Ks. 4K performance includes 4K random and continuous read and writes performance. The performance of 4K also shows the read and write performance of SSD. Therefore, it is necessary to test the performance of 4K.

But the source of what we often call “4K performance” is AS SSD Benchmark, in a narrow sense, but it is actually 4K random read and writes performance, which represents the data throughput capacity of the hard disk (measured in IOPS), and relative to continuous read and writes performance).

So what are continuous read-write performance and random read-write performance? Continuous read-write performance is the performance of reading and writing sequentially, while random read-write performance is the performance of random reads in a range.

Random reading and writing, wide range and scattered. Our SSD is also written sequentially when it is used for the first time, but the longer they use and the larger the capacity, its writes will become more scattered. Therefore, testing the random read and write performance of 4K is helpful for us to understand the read and write performance of SSD and the stability of performance.

In daily applications, the writing of web page cache and the update of system files, including the loading and response of programs and games, are all closely related to the random 4K read and write performance. it can be said that the speed of 4K read and write determines the operation experience of the system.

So it is so important for 4K performance.

However, we mentioned above that the “4K performance” measured by, AS SSD Benchmark, is a random read-write performance with a single queue and a 64-queue depth.

However, the applications we use on a daily basis cannot only read and write randomly under a single queue depth, nor can they always reach 32 or 64 queues (this depth is often used on servers). In home and small office environments, random reads and writes with a depth of 4-16 queues are generally dominant.

Therefore, the two random 4K performances (single queue and 64 queues) measured by ASS SSD are of little significance in ordinary home environments.

The 4K random read and write performance measured by AS SSD Benchmark is too one-sided.

In addition, the performance of SSD includes read-write performance and security performance.
The read-write performance of SSD includes continuous read-write performance and random read-write performance.

Therefore, it is one-sided and narrow to judge the read-write performance of an SSD by a random read-write performance or even to judge the performance of an SSD.

Generally speaking, 4K performance is important, but the narrow sense of “4K performance” measured by AS SSD Benchmark is not very important and is for reference only.

Therefore, it is unreliable to see whether the performance of SSD is good or bad only by the so-called “4K performance” measured by AS SSD Benchmark.

When we come to this conclusion, some folks with only 4K theory say, “The random performance of the group RAID0,4K has not increased, so the read and write performance of the hard disk array has not increased, and the group RAID0 is useless.” there is also an answer to this question.

03. How to test 4K performance

There are several methods for testing 4K performance, including using benchmarking software or manually testing real-world performance. One popular benchmarking software is CrystalDiskMark, which measures sequential and random read and write speeds.

• Here are the steps to test 4K performance using CrystalDiskMark:

1. Download and install CrystalDiskMark.
2. Open the program and select the SSD you want to test.
3. Choose the “4K” option in the “Test data size” dropdown menu.
4. Run the benchmark and record the results.

• Here are the steps to test 4K performance using AS SSD Test:

1. Download and install AS SSD Test.
2. Open the program and select the SSD you want to test.
3. Click on the “Benchmark” button located at the bottom right corner of the window.
4. Wait for the test to complete, which will measure the sequential and random read and write speeds.
5. Record the results and analyze the 4K performance score.

By using both CrystalDiskMark and AS SSD Test, you can obtain a more comprehensive view of your SSD’s 4K performance.

04. Factors that affect 4K performance

Several factors can impact 4K performance, including queue depth, file size, and drive capacity. Queue depth refers to the number of simultaneous reads or writes requests that the drive can handle. File size can also affect performance, as smaller files require more operations per second to access. Finally, drive capacity can impact performance because full drives may have less available space for new data.

1. Controller type: The type of controller used in an SSD can impact 4K performance. Some controllers may perform better with smaller file sizes, while others may be optimized for larger files.
2. Interface: The interface used to connect the SSD to the motherboard can also impact 4K performance. For example, SATA III has a maximum bandwidth of 600MB/s, while NVMe can provide up to 4GB/s. This can impact the speed at which data can be transferred to and from the SSD.
3. Over-provisioning: Over-provisioning refers to the amount of space on an SSD that is reserved for use by the controller to help maintain performance and prolong the life of the drive. Over-provisioning can impact 4K performance by allowing the controller to access more free space for handling requests.
4. Trim support: Trim is a command that can be used to optimize the performance of an SSD by marking data blocks as no longer in use. This can improve the performance of future write operations. Trim support can impact 4K performance by ensuring that the drive is able to maintain optimal performance over time.

By considering these additional factors, you can gain a more comprehensive understanding of the various elements that can impact 4K performance and overall SSD performance.

05. Interpreting 4K performance results

Interpreting 4K performance results can be a bit tricky, but generally, higher IOPS numbers indicate better performance. It’s important to keep in mind that real-world performance may differ from benchmark results, and different tasks may require different levels of 4K performance. However, as a general rule, higher 4K performance can lead to faster overall system performance.

06. Conclusion About 4K Performance

4K performance is an important factor to consider when choosing an SSD for your computer. By understanding how to test and interpret 4K performance, you can make informed decisions about upgrading or replacing your SSD. We encourage readers to test their SSDs’ 4K performance and use this information to optimize their system performance.

07. Frequently Asked Questions (FAQs) About 4K Performance