Hard drive installation convenience vs performance
Hard drive manufacturers over the years have improved the access time however they are still mechanical devices and as Scottie used to say, "Ye canna change the laws of physics".
A lot of cases come with convenient "screwless" mounting arrangements for hard drives and some even come with noise dampening cushioning material. So what's not to like?
When the heads of a hard drive go to data on that hard drive they do so very quickly and then come to a very abrupt stop when they think they are over the data to be either read or written. They will never be directly above the track to be read/written however. They will "wobble" a bit and it is only when the drive is certain that the heads are where they should be that the actual read/write operation begins.
So you have installed the new hard drive into your screwless 3.5" inch bay, hooked it up, formatted it and now you want to test it. You run a benchmark test and you find that your scores are lower than the ones you see in reviews of the drive online. OK, so you got a crappy drive, or the benchmarks in the review are fake - right?
That is not necessarily so. For the hard drive to work to its full potential it has to be mounted as rigidly as possible to the chassis. If this is not the case then, when the heads come to an abrupt full stop, not only will they wobble but so will the hard drive itself. Now on a brand new, empty, hard drive this may not be so noticeable; but as the hard drive gets filled and things get deleted and re-written the heads will move a lot more (until you defrag for instance) and the performance drop will be more noticeable.
Every time the heads move, if the hard drive is not rigidly connected to the chassis the vibration of the drive itself will throw the heads off and cause them to take longer to be precisely where they should be.
So much for theory what does that look like in practice?
Here are the results of my test on my Seagate ST4000DM000 HDD.15 5900 RPM 4 TB drive. I have it mounted in the hotswap bay of my CoolerMaster HAF XM case. I tested it just fitted into the caddy with the four padded mounts and the result on the program DiskSpeed was:
Access Time: 14.96 ms
Overall score: 1080.5
I then took the drive out and just added two screws to affix the drive more rigidly to the caddy and the result was:
Access Time: 14.55 ms
Overall score: 1112.7
I ran the test through three times in each configuration and I have noted the best result I got out of three for each.
As you can see, just by making sure the drive itself cannot vibrate so much it improved the "performance" of my hard drive pretty significantly. I think that's not bad for the inconvenience of just affixing the drive to the caddy more rigidly with the addition of two screws.
You have to remember that my drive only rotates at 5900 RPM and I would expect the differences in performance to be larger on a 7200 RPM drive.