3 x VelociRaptor WD5000HHTZ's: One Slower than the Other 2.

Hello,

I recently acquired three VelociRaptor WD5000HHTZ drives. Each one has firmware 04.06A00. I downloaded and installed a disk benchmarking program, CrystalDiskMark 3.0.2 x64. I'm sure there are other programs that do more things but I doubt I would know what I was looking at if I used them. I ran the program on all three drives and every time I found that one of the drives, always the same drive, for some reason has a lower sequential read and write. Why is this one drive like this and what, if anything, can I do about it?

The first set of benchmarks were completed with the SATA controller in AHCI mode.
MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]:

Code:: Test : 1000 MB [F: 0.0% (0.1/465.8 GB)] (x3) ========================================================= Sequential Read : 186.496 MB/s Sequential Write : 182.695 MB/s Random Read 512KB : 76.386 MB/s Random Write 512KB : 127.599 MB/s Random Read 4KB (QD=1) : 1.100 MB/s [ 268.5 IOPS] Random Write 4KB (QD=1) : 3.488 MB/s [ 851.5 IOPS] Random Read 4KB (QD=32) : 3.447 MB/s [ 841.5 IOPS] Random Write 4KB (QD=32) : 3.710 MB/s [ 905.7 IOPS] Test : 1000 MB [G: 0.0% (0.1/465.8 GB)] (x3) ========================================================= Sequential Read : 192.806 MB/s Sequential Write : 188.542 MB/s Random Read 512KB : 77.621 MB/s Random Write 512KB : 130.108 MB/s Random Read 4KB (QD=1) : 1.075 MB/s [ 262.5 IOPS] Random Write 4KB (QD=1) : 3.540 MB/s [ 864.2 IOPS] Random Read 4KB (QD=32) : 3.432 MB/s [ 837.9 IOPS] Random Write 4KB (QD=32) : 3.938 MB/s [ 961.4 IOPS] Test : 1000 MB [H: 0.0% (0.1/465.8 GB)] (x3) ========================================================= Sequential Read : 193.607 MB/s Sequential Write : 189.564 MB/s Random Read 512KB : 76.109 MB/s Random Write 512KB : 125.328 MB/s Random Read 4KB (QD=1) : 1.071 MB/s [ 261.4 IOPS] Random Write 4KB (QD=1) : 3.246 MB/s [ 792.6 IOPS] Random Read 4KB (QD=32) : 3.328 MB/s [ 812.4 IOPS] Random Write 4KB (QD=32) : 3.446 MB/s [ 841.3 IOPS]

I wasn't expecting the benchmark program to show me exactly the same results for each drive. Of course one drive would be the slowest of the three. However, I expected each drive's performance to be fairly close to the other and drive F: seems to lagging a little bit more while the other two drives performed about the same.

All three drives together in RAID 0:

Code:: Test : 1000 MB [C: 41.5% (335.1/806.4 GB)] (x3) ========================================================= Sequential Read : 529.250 MB/s Sequential Write : 512.250 MB/s Random Read 512KB : 85.095 MB/s Random Write 512KB : 180.961 MB/s Random Read 4KB (QD=1) : 1.169 MB/s [ 285.4 IOPS] Random Write 4KB (QD=1) : 6.699 MB/s [ 1635.5 IOPS] Random Read 4KB (QD=32) : 7.862 MB/s [ 1919.5 IOPS] Random Write 4KB (QD=32) : 11.255 MB/s [ 2747.9 IOPS]

In case you're wondering about the discrepancy of capacity: the C: drive above was actually one of two partitions on the physical drive and the original drive that was cloned to the array was only 1 TB and not 1.5 TB.

I wasn't sure what to try so I changed the order that the drives plug in to the SATA II ports. I thought maybe the motherboard has some kind of quirk which was preventing one of the drives from performing as well as it could. After I started Windows again I spent some time trying to figure out exactly which drive was assigned F, G, and H. I figured it out and gave the drives the same letters they had earlier.

Another set of benchmarks with the controller in RAID mode but no drives in an array:

Code:: Test : 1000 MB [F: 0.1% (0.7/465.8 GB)] (x5) ========================================================= Sequential Read : 187.917 MB/s Sequential Write : 184.446 MB/s Random Read 512KB : 77.672 MB/s Random Write 512KB : 127.100 MB/s Random Read 4KB (QD=1) : 1.098 MB/s [ 268.0 IOPS] Random Write 4KB (QD=1) : 3.530 MB/s [ 861.7 IOPS] Random Read 4KB (QD=32) : 3.409 MB/s [ 832.4 IOPS] Random Write 4KB (QD=32) : 3.733 MB/s [ 911.5 IOPS] Test : 1000 MB [G: 0.1% (0.7/465.8 GB)] (x5) ========================================================= Sequential Read : 192.788 MB/s Sequential Write : 189.479 MB/s Random Read 512KB : 76.210 MB/s Random Write 512KB : 131.977 MB/s Random Read 4KB (QD=1) : 1.087 MB/s [ 265.4 IOPS] Random Write 4KB (QD=1) : 3.713 MB/s [ 906.4 IOPS] Random Read 4KB (QD=32) : 3.337 MB/s [ 814.8 IOPS] Random Write 4KB (QD=32) : 4.023 MB/s [ 982.2 IOPS] Test : 1000 MB [H: 0.1% (0.7/465.8 GB)] (x5) ========================================================= Sequential Read : 194.722 MB/s Sequential Write : 191.224 MB/s Random Read 512KB : 79.073 MB/s Random Write 512KB : 127.954 MB/s Random Read 4KB (QD=1) : 1.089 MB/s [ 265.8 IOPS] Random Write 4KB (QD=1) : 3.322 MB/s [ 811.2 IOPS] Random Read 4KB (QD=32) : 3.430 MB/s [ 837.5 IOPS] Random Write 4KB (QD=32) : 3.453 MB/s [ 842.9 IOPS]

Again drive F: has a slightly lower rate of sequential read and write. I have an ASUS P8Z68-V Pro (not Gen 3) motherboard with an Intel Z68 Express chipset. I am using the integrated controllers: Intel’s (4 x SATA II ports, 2 x SATA III ports) and Marvel’s (2 x SATA III ports). I have a 1 TB WD Black drive connected to an Intel Z68 SATA III port and the three VelociRaptor drives are connected to the Intel Z68 SATA II ports. The DVD drive is connected to a Marvel port.

I also tried doing a benchmark on the slower drive while only that one drive was connected to a SATA II ports. All other drives were disconnected from the SATA II ports. The results weren’t very different.

Code:: Test : 1000 MB [F: 0.1% (0.7/465.8 GB)] (x5) ========================================================= Sequential Read : 187.681 MB/s Sequential Write : 184.657 MB/s Random Read 512KB : 77.736 MB/s Random Write 512KB : 127.737 MB/s Random Read 4KB (QD=1) : 1.095 MB/s [ 267.2 IOPS] Random Write 4KB (QD=1) : 3.484 MB/s [ 850.5 IOPS] Random Read 4KB (QD=32) : 3.439 MB/s [ 839.6 IOPS] Random Write 4KB (QD=32) : 3.765 MB/s [ 919.1 IOPS]

Any ideas or suggestions?