No it won't as the only files that are placed in the persistent cache are those which can be considered secure.
Use transient caching - if transient caching is used, a file that has been scanned, and in which no infection was detected, will not be scanned again the next time it is accessed. However, this is only valid until the next virus definitions update, as the file may contain an infection that was not previously detected but which may be detected based on the new virus definitions. Also, information that the file is clean will only be stored in the computer's operating (temporary) memory. This means that when the system is restarted the information will be lost, therefore the file will also be scanned again the next time it is accessed after a system restart. This box is checked by default; if you want files to be scanned every time they are accessed. this box should be unchecked.
Use persistent caching - if persistent caching is used, the information about the scanned file is stored in the permanent memory. This means it is not lost after a system restart and it is also not affected by virus definition updates. Consequently, persistent caching is suitable only for files which are guaranteed not to contain any virus infection e.g. operating system files, files signed by trusted publishers, or other files covered by the avast! whitelist. This box is checked by default; if you want all files to be scanned regardless of their trust status, this box should be unchecked.
It is hard to give a simpler explanation as a) as an avast user I'm not privilege to the underlying methods/rules employed to ensure that those considered safe for selection and b) ensuring they remain unchanged or would be rescanned. Basically a file that is digitally signed if changed that digital signature will no longer be valid and would mean it would have to be scanned. Before that modification occurred the real-time shields should also scan it.
Files at risk or presenting an immediate risk if infected are scanned on creation, modification, being opened (depending on scanner settings and risk) or being Run. So a new file regardless would first be scanned as it isn't in the persistent or transient cache. Subsequent to that scan it may be added to the persistent cache (if trusted publisher, signed, etc.) or if not probably the transient cache.
So essentially it takes a few scans, etc. before the cache would be fully populated and at which point those in the persistent cache won't be continually scanned until their status changes.
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So now you know they can't be added to the persistent cache, it is up to you to decide a why you chose a higher level of security and if the hit on performance (opening folders) is worth that added security.
So what changes have you made to the file system shield ?
Personally I would trust avast in the default settings as being a good balance between performance and protection, files at risk are always going to be scanned unless they are trusted files.
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You really can't compare the two AVs as you have no idea what is actually being scanned.
No one is twisting your arm to use avast.