yes, bios needs to be locked in any case (tpm or password) to prevent various attack (i mentioned evil maid one that will basically act as a keylogger)
i do agree that preboot password/pin is more secure than tpm due to the fact that with tpm if attacker has access to the entire device (not just disk drive) it can either:
- sniff communication between tpm and cpu and get dec keys
- just boot laptop and have decryption key(not the password) stored in ram (various tech including freezing ram modules can be used to extract it, or just plain bypass of win login screen)
due to various ram extraction tech, OP question is hard to answer
some rams hold memory longer than others, so immediate power off might still leave the keys in there (again this is just a theory)
as far as chiper algos goes, my knowledge is very limited
i think modern versions of AES block chipers are secure, i agree that there are some versions such as ECB block chiper that are less secure but even with them it depends on block size and key size
we are talking about potential theoretical attacks here
most of these will be very very hard to achieve, close to impossible
most people will have their security breached by some drive by virus/malware, or running software that is not trusted(i know that's not the topic)
not sure why you are against apple, i am sure you know more than i do, but i honestly find them the most secure option (nothing is bulletproof).
fun fact: some keys can be extracted using electronic microscope. chip is "stripped down", and all the boxes are read (to see which one contains, and which one doesn't contain an electron) - no actually help with this
@0xDEADBEEF said it well, most problematic part is key management
with all this limited knowledge i have, and spending a lot of mind power, some of my projects still got hacked (ex. server running on newest version of ubuntu, with newest version of apache as web server), how i don't know (login was SSH, i was not logging in with root(but even if I did doesn't change the fact), server was hosted on very reputable hosting, directory listing was disabled, cgi scripts were running by loading another script/module from outside web directory....
Nothing is bulletproof, and we shouldn't exaggerate