P35 Express – Serial ATA and RAIDTo test the Serial ATA interface, we used a Raptor WD1500ADFD and a RAID of two Raptor WD740GD. We will start with the performances in classic SATA mode with and without NCQ measured with IOMeter.
IOMeter is used to simulate the load in a multi-user environment, in this case by using a file server type load comprised of 80% reading and 20% writing, all 100% non sequential. In this type of operation, NCQ can be particularly useful. We tested IOMeter with a number of concurrent commands from 1 to 128. Obviously, with a single command NCQ doesn’t change anything and actually adds a small load on data managed by the chipset.
Without AHCI, the two chipsets are very close. The AHCI mode, which allows the use of NCQ is slightly to the P965‘s advantage.
We now move on to performances obtained with a RAID 0 (stripping) of two Raptor WD740GD, first with HD Tach :
Performances in reading cache as well as in sequential reading and writing are very close. The figures here are recorded maximum. Let’s see what happens with IOMeter :
This time the P35 Express is slightly faster than the P965.
What about the performances of the USB 2.0 interface? We carried out a series of tests in copying 2GB of files to a LaCie External HDD and then recopied it back while measuring the transfer rate and processor use. The maximum speed of the interface is also measured by addressing the cache memory of the external hard drive via HD Tach.
Here the P35 is behind the P965 with slightly lower transfer and higher CPU use that are a little higher. Of course, this isn’t dramatic but it is noteworthy.