<p>I know this isn't strictly speaking a programming question but something I always hear from pseudo-techies is that having a lot of entries in your registry slows down your Windows-based PC. I think this notion comes from people who are trying to troubleshoot their PC and why it's running so slow and they open up the registry at some point and see leftover entries from programs they uninstalled ages ago.</p>

<p>But is there any truth to this idea? I would not think so since the registry is essentially just a database and drilling down to an entry wouldn't take significantly longer on a larger registry. But does it?</p>

<p><strong>EDIT:</strong> To be clear, I'm not looking for advice on how to make a PC run faster, or asking why my PC in particular is slow (it's not), I'm just curious if people who say "bigger registry means slower PC" are accurate or not.</p>

In short, not really.
In the old days when machines were slower the answer was yes; but having a modern processor rip through even a 60MB registry is not a problem.
Typically, the real reason a modern machine starts running slow is due to everything from malware to virus scanners: Mcafee, Norton's, etc are prime targets in my mind.
Also, the WinSXS folder tends to grow as service packs and applications are installed.  This seems to have a negative impact on system performance.  There are only two possible solutions in this scenario.  First, if possible, reinstall the OS with the latest service pack already slipstreamed into the install.  Second, if that isn't possible AND you are running Vista with SP1, you can run the vsp1cln.exe tool (see
technet
) which will clean up a lot of the older versions of components.  Note that this tool can only be executed once and it does not allow you to roll back.