Testbed and Methods
The following testing utilities were used:
- IOMeter 2003.02.15
- FC-Test 1.0
- ASUS P5WDG2 WS Pro mainboard
- Intel Core 2 Duo E2160 processor
- IBM DTLA-307015 system disk, 15GB
- Radeon X600 graphics card
- 1GB DDR2-800 SDRAM
- Microsoft Windows XP Professional SP2
We installed the OS’s generic drivers for the tested drives. We formatted them in FAT32 and NTFS as one partition with the default cluster size. For some tests 32GB partitions were created on the drives and formatted in FAT32 and NTFS with the default cluster size, too. The internal drives were connected to a mainboard connector and worked with enabled AHCI. The external drives were connected to a USB 3.0 port of the ASUS expansion card or to a mainboard’s USB 2.0 port.
We guess that it would be interesting to compare not only the two external drives with each other but also the two versions of the USB standard. We will also compare USB with SATA 300. Therefore you will see four sets of data: two sets for the two USB 3.0 external drives, one for the Vantec with USB 2.0 and one for a SATA 300 hard disk drive. We used the same Samsung HD103SJ hard disk drive for each test. However, the Buffalo enclosure could not be taken apart. Therefore, knowing that the Buffalo contained a Samsung HD103SJ, we took another such drive for the Vantec and for the enclosure-less variant. Of course, different samples of the same HDD may vary somewhat in performance, yet this is the best we could do to make the comparison as accurate as possible.
We also used a 160GB Intel X25-M G2 solid state drive in a couple of tests.
Performance in Intel IOMeter
Sequential Read & Write Patterns
IOMeter is sending a stream of read and write requests with a request queue depth of 4. The size of the requested data block is changed each minute so that we could see the dependence of the drive’s sequential read/write speed on the size of the processed data block. This test is indicative of the maximum speed the drive can deliver.
The numeric data can be viewed in tables by clicking the links below. We will discuss graphs and diagrams.
The new USB version is obviously superior to the old one. The maximum data-transfer rate with USB 3.0 is as high as with SATA 300 whereas USB 2.0 is limited to 33.5 MBps. Thus, the new interface is enough for today’s HDDs. However, it is still not free from high latencies as you can see by checking out the results of the drives with small data blocks where USB 3.0 is inferior to SATA 300. Interestingly, we get the same speed when we install the SSD into the external enclosure, so there is indeed some performance limitation. We don’t know for sure if this is due to low performance of this USB controller or some fundamental limitation of the new bus architecture.
We are also surprised at the results of the SSD in terms of maximum speed. We rechecked them and even tried other SSDs, but had the same speed of 160 MBps. Yes, this is much better than the speed of 35 MBps we have with USB 2.0, but nowhere near the promised tenfold performance boost. Hopefully, this is only due to some imperfections of early USB 3.0 implementations and we will see data-transfer rates closer to the declared 4.8 Gbps in the future.
We’ve got the same picture at writing: USB 3.0 is much better than its predecessor and has enough bandwidth to service a modern 3.5-inch HDD. However, we can still see a performance hit on small data blocks. This effect is too repetitive to be accidental.