The theory goes like this: The Windows Registry grows as data is added to it, but it never shrinks when data is removed. A bloated and fragmented registry with a lot of empty space can slow down the boot time as well as performance. A Registry Defragmenter and Compactor will rebuild and re-index your registry to eliminate structural mistakes and corruption. But do you believe that a Registry Defragmenter/Compactor is safe to use and can bring about measurable improvement in start-up and performance? If so, which such tool do you use and recommend? Note: Please note that here I am NOT talking about Registry Cleaners, in which I do not believe. There are many threads on those anyway.
There are at least two ways to understand this subject. The historic one and the practical one. Historically, why the registry exists? The registry exists for a given time Microsoft considered that the model to save program settings in pure text files (* .ini) did not meet a number of demands that it possessed. Mainly by the apparent lack of organization, the excess third party changes to system files and at least the difficulty of obfuscation crucial information - mainly licensing stuff. Then it exchanged a very clear system, easily accessible to the average user and easily configurable for a model that required a special tool, the registry editor, and produce binary code now on. What is the Windows Registry? Just that, an abstraction of the .ini files written in a binary format. I come from a time that was not recommended to use wallpapers on computers, because the amount of RAM that we had available at the time did not really justify spending 1MB or 2MB only with an image that did not bring any practical effect. Today? Today you carry your entire registry in RAM, puts an array of images to be reproduced as wallpaper and it's changed over time, various wallpapers will change without you even take notice while you play MMRPG, chatting with friends on Skype, while you download and share programs, series, films, as you convert a DVD to ISO, all at the same time without any bottleneck or apparent loss of performance, all this listening to music. I know this because I've done it in a Celeron E3300 with 4GB of RAM a few years ago. So we arrived at the second part of the explanation. The practical part. The programs that sell you more performance, they do not do as promised. Stay away from them, they are not required. On the contrary, they will only be spending resources such as disk space, a bit of your processing and a bit of RAM for no earned real performance. The best program model as I have said on other occasions are programs that do not alter the operation of the system. They are generally portable programs that do not need to be installed or removed, which do not need administrative rights and can therefore be used or simply deleted when desired by the user. TL;DR: Do you wanna "fast boot"? Try a SSD NVMe/M.2, a better processor and use hibernation*. * Hibernation is half required from W8 and forward. It is default and completely transparent to the user. That's why W8 and forwards seems to boot faster. Just seems. It actually is waking from a hibernated hybrid scenario... ** Fast boots are not so big of a deal. You probably will not turn off your system today. cheers
Registry Workshop is a very good program (a registry editor) which I use. It has a "Defragment" option which I also use once in a while, just because it's there. But in terms of performance, the benefit is zero. Don't lose your sleep because this.
I use Registra Registry Manager for some years. It includes a Defragmenter too. If you do a lot install and uninstalls, you'll recognize that the Registry is like exploding in using space. The fact is, if you un-install apps most of the related Registry entries are NOT deleted, they stay simply forever. Even a (not recommended) use of a Registry Cleaner, will not delete most of that entries! Using MS'es Regedit to manually delete the left entries is a pain in the a*s and would need a long long time for to be complete. Here Registra Registry Manager jumps in! Just doing a Reseach for the left entries of previous deleted apps, it will bring those on display and it's up to the user to choose what to do next. It's simply possible to delete ALL left entries, as displayed with a few clicks of your Mouse! There still a few entries, which are protected by the OS which couldn't be deleted that way. To get them out too, a boot from an extra OS is needed and do the work from there! To be very honest, to edit, change, adjust, or whatever you like to do with your Registry, you'll need really to know WHAT are you doing, it's simply dangerous! First at all, BEFORE you do anything on your registry, make a Backup of it! Never edit a Registry, without having an updated Backup!
Id also like to add to pisthai's post, once you make a backup. You need to know how to restore the backup as well. Especially in the event you cannot boot into windows. Saving yourself the inconvenience and trouble of trying to fix your install. Many of us here stress the importance of backing up the entire system to an image in case of catastrophic system failure. Of course this only applies to those who actually use their computers and have something of value (to that person) on it. If the data and system lack any importance and you have free time, no need to worry about backups then lol
A registry backup, though mandatory before working on it, shouldn’t be regarded as foolproof safeguard. As EFA11 pointed out, you may not be able to start the computer. Once after an intervention, I couldn’t even start it in Safe Mode. But apart from that, a problem may not appear immediately after an intervention, but much later when you try to do something you don’t do often or do something for the first time. It will then be difficult to attribute the problem to the work you did on the registry. Plus, you may not want to turn your registry so far back in time. Thus, prevention being better than cure, if Registry Compactors can cause damage, it’s better to leave them alone. But the question remains as to whether they are really risky, as they don’t change the registry, only rid it of gaps.
I do Registry 'cleaning' and defragmenting for years already, and also know very well how to restore the Registry in case of the OS isn't able to boot up anymore. Just, I wouldn't 'teach' someone on any Forum the How to....., to simply avoid the insulting, harassment and more,after a user get some problem which he couldn't handle and pointing the finger on those to gave the information (in what way ever)! Special on this forum, are quite some members who like to do that! Anyway, a user with just a basic knowledge, should never even think about to touch the Registry! If he/she didn't know how to backup and restore in extreme situation, keep the hand (and brain) off from such work and actions! And that include also the use of Compactors, while most of them not just get rid of gaps, they moving parts of the Registry entries around, and also sometimes deleting required space, which ends up (in some cases) to get excluded Registry entries back to work! My only really honest advice, if I would gave one, would be: get all required knowledge for all different aspects, from a really reliable source (not a Forum) if done 1 and the User is confident he/she has that knowledge, backup the registry at least twice to different places do the editing as planned defrag the Registry Test! If the test went OK, you're done, and now, the first step is, backup the registry again to a new location, for to be sure, even to have a Backup in case off! If the Test wasn't OK, start the restore process. I use to have for that a special prepared USB bootable HDD with OS, and that saved me a lot of time 3 times in the last 5 years! All other times, which were a lot over the years, simply went OK, because I know exactly: WHAT to do WHEN! Good luck.