Hard Disk Speed Question

G

Guest

Guest
Hi,
Yesterday I reinstalled Windows as it was starting to play up.
Now, since doing this, I think my HD has been performing slower.
I have a WD5000AAKS connected through sata connection. So theoretically, as my mobo doesn't support sataII, am i right in thinking my max rate is 150mb/s?
I have downloaded a HD performance tool and have taken a screen shot:

That was taken when transferring some data from one partition to another on the WD drive.
From what I can make out, it says the max transfer rate at around 78000KB/s, with the graph in the bottom right corner actually averaging around 48000KB/s.
I would just like to ask is this normal? It just seems slower that it was before.
Cheers,
James
 
SATA 1 is limited to 1.5Gbps, or about 200 MB/s. That's a lot more than a hard disk can do these days, so it won't really be a bottleneck.

If your performance has dropped after reinstalling Windows, maybe you need to install some WD software. Did you get a CD with your disk? Visit their Web Site, get the latest drivers.

I can tell you that WD5000AAKS is awfully slow compared to newer drives with perpendicular recording like the WD7500AAKS. I can see the difference easily because I have both types in my PC. For example, with the WD5000AAKS, DVD Shrink adds up to a cache of 1.2 GB and then stays there at the end for two minutes to flush it. With the WD7500AAKS, the cache stays under 100MB and the final 2 minute wait is gone.

 
OK first off, SATA II or SATA (300MB/s vs 150MB/s) is the maximum theoretical bus speed. The only time you'll see transfers approaching this is with burst speed (ie from controller to cache). Burst speed is essentially useless as an indication of HDD speed.

As for testing the drive in the fashion you did (transferring some data from one partition to another on the WD drive), I am surprised it stated the speed it did if my assumption is correct. If you were transferring data from one partition to another on the same physical drive, you won't see your maximum speed as the drive has to read from one location and then move the head to write to another. To test it in this manner with the program you are using, transfer data from one physical drive to the other. Unfortunately the slower drive will be the bottleneck, so if the slow drive isn't the one your benchmarking, this method won't work well either.

If you need to benchmark you HDD, use SiSoft Sandra, HDD Tach, HDD Tune, and/or IOMeter. IOMeter is a very complex benchmarking utility and the one I would recommend the least because of it. HDD Tune and HDD Tach are probably the easiest.

Also if your HDD seems a little slower after the re-install, I have one question, have you defragged? Windows has a tendancy to scatter pieces of files all over during installation, so you may find that the slow down your perceiving will go away after a good defrag.

Hopefully this clears up some misconceptions and helps as well.
 
G

Guest

Guest
Cheers techgeek, that is a very helpful post.
I had the idea last night that a better test would be to transfer from one physical drive to another, but unfortunately it is the fastest drive in my PC.
I haven't tried any defragging yet. That will be my next step. I'll then try the recommended HDD tune to benchmark it.
I'll post the results later on.
 
Actually I just had another thought, though it is quite likely you know what you are doing. You installed your chipset drivers following the installation of windows? Again just a thought, and something that could be easily overlooked.
 
G

Guest

Guest
Yeah, installed chipset driver.
Defragged earlier, and just run HD Tune benchmark test. Result is as follows:

Does this look normal?
I don't want you to get the wrong idea, my machine is by no means slow. Its just I thought it was faster before, and I want to make sure i'm getting the most out of my hardware :)
Do you know why the speed get slower as time increases in the benchmark test?
 
Do you know why the speed get slower as time increases in the benchmark test?
All traditional hard drive benchmarks are like that. It's because it starts to measure from the outside of the spinning platters. At the same rpm, the outside surface of the platters is moving faster than the inside surface. Go back to your childhood days of riding on a merry-go-round. If you sit in the center not much happens, but if you're on the edge you feel like you're going super fast.
 

godless

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or if can think of a dvd burner, it's just the opposite of that. first it's slower because the radius is smaller. but then it slowely picks up speed. so that when it's writing the last gb, it's at it's fullest potential. these test start with the highest and go to lowest. that's why it gives you the top speed/ min. transfer rate and of course the average.
 
Usually before i reinstall I write zeros across the entire drive to avoid any potential issues. you can download WDdaig boot cd from western digital and use that to set the drives to the way when they came out of the box. you will lose everything