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Our team has talked a lot in our previous articles about Disk Defragmenter and the changes introduced in Windows Vista and Service Pack 1. In this article, I would like to measure how system performance is affected by the defragmentation process. Basically, I want to find out what is the performance hit on your system while this tool is running and defragmenting your data. To see the results and conclusions of my analysis click on read more.
The PC on which all tests were run has the following configuration:
To analyze the level of fragmentation on my hard disks, I used Defraggler, a free defragmentation tool. As you can see in the screenshot below, my system drive 'C:' had a total of 429 fragmented files which represented 6 GB from the total of 22.4 GB of used space.
To run the benchmark, I used Disk Defragmenter and not Defraggler, as the expected results must come from the Windows Vista tool. I had configured it to defrag only my system drive 'C:'.
How I did the testing?
For benchmarking, I used PassMark PerformanceTest, version 6.1. I ran all the tests found in this application, except the 'CD Drive' test which is not affected at all by the defragmentation process. The tests I ran were the following:
After performing these tests, PassMark PerformanceTest shows a mark for each of them and a general PassMark Rating. This rating is a weighted average of all the other test results and gives a single overall indication of the computer's performance.
The tests were ran before starting the Disk Defragmenter to record the baseline of results. Then, I launched Disk Defragmenter and started the defragmentation process for the system drive 'C:'. During the defragmentation process, I ran the same tests, saved the results and compared them with the baseline.
As you can see in the screenshot below, the overall performance difference is quite small. The PassMark Rating has only decreased with 2.5%, from 647.4 to 631.3.
Going into more details, I noticed that there are areas where the defragmentation process has no negative impact. For example, it doesn't seem to affect at all the CPU and Memory performance: the results of the CPU Mark and Memory Mark tests actually increased with 0.7% and 0.5% respectively during the defragmentation process. While it is hard to explain why there is an improvement in these tests, it is very good to see that there is no negative impact. I have repeated these tests a few times, and there was always a very small increase in results (up to 0.7%).
As expected, the areas which are influenced by the defragmentation process are the graphics and hard disk performance. During the 2D Graphics Mark test, the results decreased by 8.5%. For the 3D Graphics Mark, the difference was even bigger, the final results showing a decrease of 11.8%.
The results of the Disk Mark test showed a decrease of 2.1% in performance. Even though I expected to see a decrease, it is good to see that the impact on disk performance is not that high.
The results of the benchmark were surprisingly positive. Unless you want to play games on your PC or you need to use applications which intensively use your hard disks (e.g. simultaneously downloading many files through file sharing clients), the performance impact is negligible. An impact of only 2.5% on the overall system performance during the defragmentation process is a small price to pay, considering the benefits of regularly defragmenting the data on your hard disks.
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