Microsoft → Re: Registry: What Does XP Do to Keep It In Shape?

If you download and install programs a lot, then it is important to maintain your system registry. As someone else mentioned, you would be surprised at what gets left behind.

I'm the type that tries a lot of different programs, just to see what they do, how they perform, etc. Generally after the trial period I uninstall and try something else. Uninstall routines normally don't remove everything, esp. after a trial expires. I run CCleaner and System Mechanic to remove junk. However, they both togather don't often remove everything. And then there are those times when a file (dll, exe, etc) gets corrupt and a reinstall is needed. HP multi-function devices are agood example. You have to go into the system registry and manually search and remove entries in order to do a re-install.

One of the biggest reasons to keep your registry in shape is (partly) due to performance. When you start your pc (or reboot for that matter), the system registry is one of those things that, at least, in part gets loaded into memory. The larger it is, the more time it takes to load. For me, I like to keep my system as highly tuned as possible. This includes cleaning the system registry, defragging, etc.

Do you have any numbers to back up claims of improved performance?Nothing gets 'loaded' that isn't used (to a first approximation).

The registry is mapped into the system address space. Parts of the registry are faulted into real memory as they are touched. Parts that aren't touched, e.g. leftover keys that no-one reads, have no reason to end up in real memory.

I admit I'm discussing from theory rather than practical experience. But there's no reason why truly unused parts of the registry need to be placed in real memory. That's just not the way virtual memory systems operate.

There is an effect that 'too much' junk interleaved with non-junk can cause the parts that you do read to occupy more pages than would otherwise be the case. So from that point of view, large is worse, and large does cause more disk I/O.

My challenge to you is to actually measure the difference, because if you can't measure it, it doesn't matter.

I think youre right, but im my own experience .. and for my own comfort .. I like to keep a tidy system and not have to wonder about funky behavior or strange system issues.

This comes in conveniently and handy when its been maybe a year and you think about a fresh start and format. I havent been able to afford a format in 2 years and my upkeeping of the system i feel plays a big role in _not_ needing it.

It's simply not true. They do have "reason" to end up in memory - see below.Exactly! Junk is never concentrated in one place of registry. So, the more junk - the more registry should be loaded in memory (read - less efficiency per load).

Second point. If, for the sake of discussion, we even assume that all registry is already loaded into memory (there is no memory faulting overhead) don't tell me that time required for all registry operations does not depend on the size of the data container (registry). As far as I know it's not an array.

And the last point - as far as I can recollect (fix me if I'm wrong here) m$ prohibits users/companies from measuring and publishing results from such measurements of Windows performance. So, asking users - give me measured comparison - is not, let me put it this way, quite fair. At the same time I have to admit - I'd like to a see it done in a professional manner as well.

No, it'll likely be some sort of tree, which means the access time is O(log N).

So if you double the size of the registry, i.e., it's 50% wasted junk, you'll add one extra lookup.

Bet you can't measure it.

You hit upon the real reason why most people mess with these utilities I think: fastidiousness, not necessity. If any given task will not give you a performance boost then why bother doing it? Especially when the task has the potential of doing more harm than good. Wholesale cleaning of the registry is akin to flashing the BIOS in my estimation: it should only be done when it offers an advantage over not doing it. And as dave noted that *might be* and I stress might be necessary every year or two but certainly not weekly or even monthly as a routine maintenance task. However, if one is obsessive/compulsive I guess no amount of reason will dissuade them from that mindset.

Just a note: what to do about all those unused registry entries for the external devices I have? Since I don't have them plugged in all the time wouldn't I get better system performance if I removed them until they're needed so the machine would boot faster? Of course not. My point is that while orphaned registry entries may make you "feel" better about the cleanliness of your registry that doesn't equate to an actual benefit to the system, only to your mental health.

You're exactly right. Sounds like most of the people replying to this don't really know what gets saved in the registry to begin with. CCleaner is a good program for cleaning the basic stuff, and would be sufficient for the average joe. But anybody that REALLY knows what they're doing cleans the registry thoroughly with things like Easycleaner and others that that can dig a little deeper.

Either that, or they use Linux and don't have a registry!