Product Review: A-DATA USB Flash Drive PD9 16 GB (for Mac & Windows): Using USB Memory on Mac OS X Leopard and Windows XP

A-Data USB Flash Drive PD9
Mac product review






More than 15 years ago, Apple introduced System 7. It was an unprecedented operating system, compared with its predecessor System 6.0.8, that came with many new software features. One of them is RAM Disk. RAM Disk allows the user to create a volatile, virtual disk where you can store data. Mac OS X doesn’t support RAM Disk. But there are several freeware/shareware solutions for creating RAM Disk under OS X. One advantage of using a virtual disk is its fast Read/Write speeds. One major disadvantage is… Of course, it’s volatile. If a Mac suffers a sudden system error, you can lose entire data stored in a virtual disk.

If you don’t want to allocate a small share of fast, random access memory, there’s a different way of creating a virtual disk at low cost. How about using a USB memory stick? Prices for USB memory sticks are quite affordable these days. You can find a 16-GB USB memory stick for $50 to 60. And we purchased A-DATA USB Flash Drive PD9. In fact, it’s our first experience in using a USB memory stick. And our initial, innocent questions were





  1. Are Read/Write speeds different, depending on whether you use it with USB 1.1 or 2.0?
  2. Does the disk format matter when it comes to the Write speed?






One major reason why we wanted to test a USB memory stick is to find a good data storage medium for swapping data between Mac OS and Windows through Boot Camp. And the USB memory stick can be a good candidate because its memory is not volatile. And many USB memory sticks are compatible with both Mac OS and Windows without an additional hardware driver. 





A-Data USB Flash Drive PD9
Screenshot 01: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 02: Source – MacHouse






As you probably know, recent Mac models are equipped with 3 USB 2.0 ports. You have two additional USB 1.1 ports on the keyboard. Furthermore, depending on whether you insert a USB memory to a port in the back (See Screenshot 01.) or on the keyboard (See Screenshot 02.), Read & Write speeds can potentially differ. USB 1.1 (Full Speed) can transfer data at a rate of 12 Mbit/s (1.5 MB/s). And USB 2.0 is designed to transfer data at a rate as fast as 480 Mbit/s (60 MB/s).





A-Data USB Flash Drive PD9
Screenshot 03: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 04: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 05: Source – MacHouse






When you first stick A-DATA USB Flash Drive PD9 (hereafter, A-DATA USB Flash Drive) to either a USB 2.0 port in the back or a USB 1.1 port on the keyboard, a disk icon will appear. It’s labeled NO NAME. (See Screenshot 03.) Let me change the disk name to something more appropriate, say, USB MEMORY. (See Screenshot 04.) Is this name going to be static? Let me restart my Mac (iMac Core 2 Duo 2.8 MHz). After restarting it, the USB disk is back with the name unchanged. (See Screenshot 05.)

Next, let me launch Disk Utility. I want to use Disk Utility to check the default disk format of A-DATA USB Flash Drive. Screenshot 06 shows that the USB disk is initially formatted with FAT (file allocation table), which is used by DOS and Windows. So if I put a file in this USB disk and then switch to Windows, both the disk and the file should be recognized, right? Let’s test that.





A-Data USB Flash Drive PD9
Screenshot 06: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 07: Source – MacHouse






I have a folder titled VirtualDub, which I downloaded under Mac OS X. This folder contains the zip version of a video-compressing freeware title for Windows OS. So I’m going to copy it to A-DATA USB Flash Drive. After switching to Windows XP on my iMac Core 2 Duo, let me open My Computer. And I find Removable Disk (F:). (See Screenshot 07.) If I open the disk… Yes, I find the same folder that I copied under Mac OS. (See Screenshot 08.) So we can use A-DATA USB Flash Drive to exchange data between Mac OS and Windows with no problem. Wait… Let me copy 4 graphic files to A-DATA USB Flash Drive under Windows XP and then switch back to OS X Leopard. And I find the same files in A-DATA USB Flash Drive. (See Screenshot 09.) So my earlier statement holds.





A-Data USB Flash Drive PD9
Screenshot 08: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 09: Source – MacHouse






So how fast can our iMac write data on A-DATA USB Flash Drive? What I’m going to do next is to copy 3 folders containing Windows files to A-DATA USB Flash Drive. (See Screenshot 10.) The total data size is 46.6 MB. And it’s going to take… More than 1 minute… (See Screenshot 11.) Actually, it turned out that it took 2 minutes and 4 seconds. If I copy 72.2 MB of data to A-DATA USB Flash Drive, it takes 3 minutes and 52 seconds. Furthermore, if I try to copy about 4 GB of data to A-DATA USB Flash Drive… It looks like it’s going to take more than 1 hour. (See Screenshot 12.)





A-Data USB Flash Drive PD9
Screenshot 10: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 11: Source – MacHouse
A-Data USB Flash Drive PD9
Screenshot 12: Source – MacHouse






The disk format is FAT32 for now. What if I re-format the disk to Mac OS Extended? Will the Write speed improve? And we timed the Write speed through USB 2.0. What if I use A-DATA USB Flash Drive under USB 1.1? Will the Write speed get a lot worse? So, again, we copied 72.2 MB of data to A-DATA USB Flash Drive and measured the Write time for each case. Results shown below don’t look good.





Format/USB Time
     Mac Extended (Journaled) USB 2.0 3:54
     FAT 32 USB 2.0 3:52
     Mac Extended (Journaled) USB 1.1 3:57
     FAT 32 USB 1.1 3:16

The date size: 72.2 MB






Obviously, the Write speeds are hindered by an unknown cause such that it doesn’t really matter if I use USB 2.0 or 1.1. How about the overall Read speed? I copied a 22.6-MB file stored on A-DATA USB Flash Drive to Drive C under Windows XP. And it took only a few seconds. So the Read speed shouldn’t be a problem.

What does A-DATA have to say about these results? We contacted the manufacturer and asked if there is a solution for improving the overall Write speed under Mac OS some 40 hours ago. And a support representative replied in a timely manner. He or she wrote






The problem might be caused by the CONTROLLER inside the disk. But it’s true that the disk can work well. We do not have any solution to solve
suggest you except choosing speedy disk. We are so sorry for it.
(See Screenshot 13.)






That’s too bad. It’s true that the price speaks itself. So we can’t expect a great performance on this USB memory stick. But the Write speeds shown above are more than unacceptable, aren’t they?





A-Data USB Flash Drive PD9
Screenshot 13: Source – MacHouse





  • Product: USB Flash Drive PD9
  • Manufacturer: A-DATA (www.adata.com.tw)
  • System requirements: Mac OS 9 or later, Windows 98/98 SE/Me/2000/XP/Vista, USB 1.1 or 2.0
  • Street prices: US$47.95 ~, ¥5,100 ~
  • MacHouse recommendation: The overall Write speed doesn’t look good. So if you are looking for a better overall Write speed, this particular USB memory model may not be of your choice.






    P.S. How about the Write speed under Windows? It takes the same computer (iMac Core 2 Duo 2.8 GHz) under Windows XP 60 to 70 seconds to copy 354 MB of an AVI video clip to USB Flash Drive.






    USB Flash Drive PD9 is a product of A-DATA Technology.





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    * We have purchased the product introduced here ourselves. We are not being paid to review this product in any way.

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    3 Responses to Product Review: A-DATA USB Flash Drive PD9 16 GB (for Mac & Windows): Using USB Memory on Mac OS X Leopard and Windows XP

    1. SIRAJULHAQUE says:

      i purcased ADATA 4 GB falsh pin drive.it worked only a month and then it is not formatting by windows even every test of usd drive shows that”this device is working properly.i sent e mail to ADATA they reply to test it on other computer.i send them the whole detail but now they are not replying.WHY THEY CLAIM LIFE TIME WARRENT WHILE THEIR PRODUCTS DOES NOT WORK FOR A SHORT PERIOD.TO WHOME I ASK FOR HELP???SIRAJALHAQUE

    2. I’m sorry to hear that. I hope they’ll give you a replacement.

    3. This USB memory stick is finally broken 2 years after purchase. Data cannot be read, and the volume cannot be formatted.

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