Four USB Flash Drives from A-Data with 4GB Storage Capacity

For our today’s article we picked four USB flash drives with 4GB storage capacity from A-Data Company. WE are going to check out their performance compared against other 4GB solutions available in the market and see how well they cope with Windows Vista ReadyBoost function.

by Andrey Kuznetcov
11/21/2007 | 03:51 PM

For our today’s article we picked four USB flash drives with 4GB storage capacity from A-Data Company. The flash drives of such capacity have already become quite affordable for most users out there. Although the performance and speed characteristics of USB flash drives keep improving day by day, we can still sometimes come across certain models that have fallen below today’s performance standards.


Here we first of all imply ReadyBoost technology implemented in the new Microsoft Windows Vista OS that allows to speed the system up in case certain specific conditions are met. The main condition here is the performance of the USB flash-drive with ReadyBoost feature. Another factor that we take into account in tests like that is the possible performance difference between devices within the same product family that feature different storage capacity. So, we decided to check things out with the help of USB Flash drive solutions from A-Data.

In order to be able to more objectively estimate the performance of our today’s four testing participants we decided to compare them against solutions with the same storage capacity that we have already tested before (see our article called Roundup of USB Flash Drives with 4GB+ Storage Capacity).

Let’s take a closer look at our today’s testing participants.

A-Data My Flash RB15


The drive case is made of black rubber. This casing is water and shock resistant thus protecting the device in extreme conditions. There are white plastic pads on both sides of the drive that make the whole exterior design look a little livelier. There is a special loop at the end of the casing where the transportation band goes. There is also a green status LED. The USB cap sits tightly on the drive, so you are unlikely to lose it.

The device comes packed in a standard plastic box with no additional accessories.

A-Data My Flash PD15


This is a highly compact device: you can feel it the moment you take it: the black plastic casing is thinner than a match. As usual, they had to make some sacrifices for the sake of this extremely miniature size: the simplified implementation of the USB connector makes it a little harder to plug the device into the USB port of your computer. You can carry it on a wrist or neck band that goes through a special slit in the casing.

The device is shipped with no additional accessories.

A-Data My Flash PD14


At first glance the USB Flash drive case seems to be made of aluminum, but if you take a closer look you will see that unfortunately, it is made of plastic with “metal-like” finish. The USB cap sits very tightly on the connector, so you will hardly lose it (unless you leave it somewhere). At the rear end of the drive case there is a small metal loop for the transportation cord fastening. Right next to it there is a green status LED indicator.

The device comes with no additional accessories.

A-Data Oriental Elite 120x PD3


In this case we see a solution that looks fancy enough to be a nice gift to somebody. You get this impression from just looking at the package it comes in. The box that contains a USB flash disk drive features magnetic locks, black velvet insides and really rich accessories bundle compared with the previous three solutions we have just mentioned. The plastic casing of light-purple color has a second transparent skin on top. Through this skin you can see paper inserts with Asian inscriptions on both side of the drive. The USB cap is also made of transparent plastic and is decorated with Asian dragon images. There is a green LED status indicator on the drive and a hole in the rear end of the casing for the transportation cord.

The device comes with a USB extender cable, miniature CD disk with the driver, a transportation cord and two replacement case stickers.

Testbed and Methods

We used the following test programs:

The testbed was configured as follows:

We are still using two versions of FC-Test utility for our benchmarking session. Although they differ in some points of their test algorithms it allows us to compare the results of the flash drives with those that we have tested earlier.

Performance in Intel IOMeter

Sequential Read & Write Patterns

As usual, we will start our session with the synthetic IOMeter benchmark measuring linear read and write speeds. This pattern allows measuring the drives’ sequential read and write speed on data blocks of different size (from 0.5 to 1024KB).

To make it easier for you to read the charts we will highlight the today’s four testing participants with read color.

The linear read speed graphs you see on the first chart indicate that our testing participants didn’t set any speed records. Nevertheless, we have every right to admit that RB15, PD3 and PD14 flash drives perform at a very decent level here. The only exception was the PD15 drive that yielded to almost all its opponents in this linear read speed test.

The situation with linear writing is completely different. PD14 and PD15 flash drives stand out here, as their performance is considerably lower than that of most other products. Moreover, we have to draw your attention to the fact that PD14 features very low sequential write speed when working with small data blocks. At the same time, you can see that although PD3 and PB15 cannot really compete with the fastest flash drives in this test, they are not among the outsiders either, their results are more than satisfactory.

Random Read and Write Patterns

Now let’s evaluate the flash drives performance in random read and write patterns. These parameters are very important for everyday use of USB flash drives as work drive, and not only file transportation means. During our tests the data block size varied from 0.5 to 32768KB.

The first diagram shows the average access time each of the flash drives demonstrated during data reading. The slowest of the four today’s main testing participants appeared PD15 drive – it is the last but one on the list. PD14 did a little better, and RB15 and PD3 drives didn’t give us any reasons to be concerned: although they didn’t become the fastest of all, their performance was more than normal.

In case of random writing PD15 and PD14 appeared evident outsiders – only one Kingston flash drive appeared slower than them. The situation with RB15 and PD3 is much better: although their random writing time is not the absolute minimum, they are not falling too far behind the leaders.

Average Access Read & Write Time

It is also very interesting to check out the average read/write access time. In our case we are talking about the access time when flash drives are performing random read and write operations on 512Byte blocks. The end values are calculated basing on the results of a 10-minute test to read/write 512-byte data blocks at a request queue of 1.

When we measure average access time during reads all four today’s testing participants from A-Data turned out next to one another on the result diagram. In this case we should just be happy for the manufacturer: they have hardly yielded anything to the performance leader in this test.

As for the average access time during writes, the picture is different and not as rosy anymore as in the previous case. The results of PD15 and PD14 flash drives are the highest (smaller is better in this case, though. The other two solutions found themselves in the middle of the chart: nothing to be upset about, but also nothing to be really proud of.

Windows Vista ReadyBoost

The gradually growing popularity of the Windows Vista operating system makes it more and more adequate to test their ability to boost the computer storage system performance (with the help of ReadyBoost technology). As you know, Windows Vista performance may be increased with the help of a regular flash drive that may function as additional cache with lower access time as that to the system hard disk drive. Of course, these flash drives should meet certain requirements: they should be at least 256MB big and be fast enough to ensure at least 2.5MB/s data transfer rate during random 4KB block reading and at least 1.75MB/s during random 512Byte blocks writing.

The OS itself tests the USB flash drive connected to the USB port. The tests are performed for two above described modes and in case the results are good enough the system offers to employ ReadyBoost technology. However, we decided to use Intel IOMeter for more precise results. The performance was tested during a 10-minute test.

Purple and red colors on the diagram below stand for the results of those flash-drives that have successfully passed the performance test. Baby-blue color stands for the ones that failed.

The diagram for random reading of 4KB blocks shows that all four today’s A-Data solutions demonstrated much better results than the minimum required for proper functioning of ReadyBoost technology. Even the slowest one, PC14, took one of the middle spots in the ranking chart.

Unfortunately, the picture is not so nice during write speed tests. Nevertheless, all our testing participants managed to get past the sacred threshold for ReadyBoost (minimum 1.75MB/s speed). PD15 and PD14 had the biggest difficulty with it. Two other flash drives coped just fine with this task and took two neighboring spots on the ranking chart. Although about half of other solutions still proved to be faster.

Performance in FC-Test 1.0

FC-Test will help us examine the flash drives under real-life conditions. As usual we will use two versions of this test utility, although the second one is more precise. However, we need to be able to compare today’s results with those obtained before we developed FC-test 2.0.

Let me remind you once again how this program works. The program writes and reads a few file-sets of certain size and number of files and measures the time it takes to perform each operation. This helps calculate the speed of the drive and see how it depends on the number and size of the processed files.

In our case we use three file-sets. They differ in file size (1, 10 and 100MB) and number of files (1, 10, and 100) from one another. Practice suggests that a 100MB file is large enough to reveal the maximum performance of a USB flash drive and using a larger file doesn’t affect the results much.

The first diagram shows the write speed for 100 files 1MB each. PD14 and PD15 drives proved evident outsiders as their results are the lowest of all the tested drives. The fastest of the four is RB15 although it is still pretty far behind the leaders. This drive, as well as PD3 can be called a confident average performer.

When we read 100 1MB files, the picture is more systematic. RB15 and PD3 again proved to be the fastest of the four A-Data products tested today. However, their performance is pretty average against the background of other solutions. PD15 remained an outsider having taken the last but one spot.

When the file size increases to 10MB, all of our main testing participants managed to improve their performance, although it didn’t really pay back in general: most of their competitors boosted their performance even higher. As a result, our heroes took the lower part of the ranking chart, with PD14 and PD15 falling considerably behind the others.

Reading 10 files 10MB each doesn’t change anything in the situation. RB15 and PD3 perform very closely and rest in the middle of the chart. PD14 yields a little to them, while PD15 again turned out almost the last.

When the size of the test file increased to 100MB, all four flash drives again improved their write speed. But again, it doesn’t change the picture: all four are in the bottom part of the chart.

The results of RB15 and PD3 are identical again during reading of a 100MB file. They took the middle spots on the chart. The PD14 is just a little behind them. the slowest of the four here is again the PD15: it appeared almost 1.5 times slower than the other in this test.

Performance in FC-Test 2.0

Now let’s check out the results obtained with the second version of FC-Test utility.

PD14 writes a hundred 1MB files slower than all others. PD15 also stayed close. However, RB15 and PD3 look very nice in this test: although they are not the fastest of all, they took two of the top spots on the chart.

The diagram for reading a hundred 1MB files shows that there is no huge gap like the one we saw with writing. RB15 and PD3 drives perform averagely well, with PD14 falling just a little behind them. PD15 again the last but one here, but the lag is not that dramatic as during files writing anymore.

All four heroes of our today’s review take the lower part of the ranking chart during writing 10 files 10MB each, although I have to stress that RB15 and PD3 outperform PD15 and PD14 significantly.

Reading 10 files 10MB each is yet another proof that all four are pretty persistent with this type of tasks: RB15 and PD3 are again in the middle of the chart. PD14 a little behind them and PD15 took the traditional last but one spot.

Only BR15 and PD drives demonstrated acceptable results when writing a 100MB file, although we cannot call it remarkable. PD14 and PD15 drives again are almost half as fast.

Reading a 100MB file doesn’t change anything. RB15 and PD3 drives again performed up to the mark. PD14 again was just a little slower, and PD15 retained its last but one spot.


We tested four flash drives from A-Data with 4GB storage capacity. Summing up the results I would like to start with the slowest one and move up to the fastest.

The main advantage of the A-Data PD15 drive is its compact size. Although its miniature dimensions may cause certain problems when you try to plug it into a USB port. Moreover, it is not the fastest: if the read speed is more or less fine, then the write speed is way below the today’s requirements, even though it passed the ReadyBoost compatibility test just fine.

A-Data PD14 flash drive with a little more traditional exterior design tested better than the previous model. Its read speed in our tests was quite up to the mark, but the writing put it side by side with the PD15. Its writing performance drops down dramatically when the drive has to work with small data blocks. It also complies with ReadyBoost requirements just fine.

A_Data RB15 flash drive is remarkable for its waterproof design and very decent and well-balanced performance characteristics. It didn’t set any performance records, but demonstrated stable performance in our tests and went far past the ReadyBoost compliance threshold.

Finally, A-Data PD3 flash drive will make a great gift thanks to its unique accessories bundle, stylish exterior design and packaging. Moreover, it also boasts pretty good performance showing very similar results to those of RB15. Of course, it is also fully ReadyBoost ready.

So, of four A-Data solutions we would recommend taking a look at PD3 or RB15 depending on the type of tasks you are after and your personal preferences.