X-bit labs

WD740GD aka Raptor 2 Hard Disk Drive Review (page 10)

Category: Storage

by Nikita Nikolaichev

[ 02/18/2004 | 11:37 PM ]

Performance in Intel IOMeter WorkStation Pattern

Now let’s test our new Raptor in WorkStation pattern. Theoretically, the situation in this pattern is favorable for WD drives as they have to work under low loads and perform a lot of writes. Anyway, let’s check out the results:

In fact, the situation is very similar to what we have just seen in server patterns. Although the access time of our WD740GD is close to that of the participating SCSI solutions, our hero is considerably faster under low workloads. But as soon as the workload reaches 4 requests, SCSI drives outpace the winner.

On the other hand, high HDD speed under high workloads doesn’t matter that much for desktop applications, because they are not typical of desktop systems.

That is why we will calculate the performance rating for WorkStation pattern in a bit different way. Unlike server patterns where we consider all workloads to be equally probable, here we have to introduce probability coefficients for large workloads so that we could reduce their weight for the final result. The weight coefficient for the HDD performance under certain workload is inversely proportional to the queue depth.

Performance = Total I/O (queue=1)/1 + Total I/O (queue=2)/2 + Total I/O (queue=4)/4 + Total I/O (queue=8)/8 + Total I/O (queue=16)/16 + Total I/O (queue=32)/32

Now let’s see what we’ve got:

Due to a significant advantage over the SCSI drives under low workloads, the new WD740GD looks very attractive overall.

However, when we run the tests within a 32GB partition, the situation gets somewhat different: the victory belongs to a 73GB HDD from Seagate. Although WD740GD is still faster than the leader under linear workload, it is unable to break ahead in the 32GB partition, where the SCSI drive receives an indisputable bonus from the TCQ.