turbocache, shared and dedicated memory

hi there, just wondering mainly what the difference is between the three types of memory. i get dedicated, thats easy, memory specifically used for games. but, i'm concerned about how much the graphics suffer from using turbocache (or shared) memory as opposed to using dedicated. and i don't actually know if turbocache and shared are the same thing.

i'm looking for a laptop right now and all i'm getting is 1023mb shared with 256mb dedicated. does this mean that if the game needs more memory it'll use 1023mb of system RAM then give it back when its finished with it? and will this deteriorate normal system performance because its also used for games? because i've heard that according to the system it will sometimes only recognize , for instance, if you had a system with 1024mb of RAM, and 256mb of memory shared (or turbocache), it appears as having 768mb of RAM because the shared memory is used for games and not sysem processes. or is that specific to shared memory only systems?

i know its alot of questions but i'm dying to work all this terminology out, so any input would be greatly appreciated, thank you!

Jam it back in, in the dark.

but the thing is most of the cards integrated into laptops do have shared memory, i don't think i've been able to find a solely dedicated graphics card, there's always shared memory with it.

edit: slightly off subject, but does anybody of any laptop customize sites apart from alienware? they're kind of expensive.

There's nowhere I can't reach.

just out of curiosity, what would be better? a solely dedicated card or a dedicated card with shared memory?

This thing is sticky, and I don't like it. I don't appreciate it.

ah, thats interesting, if you go to customize a laptop on alienware, they only specify the dedicated allocation. does that mean that it has shared memory and they're just not telling you?

I am a dolphin, do you want me on your body?

so basically look for the dedicated memory allocation and the more shared memory the better?

I was speaking idiomatically.

thanks very much, thats cleared everything up, liquidacid. so they only tell you the shared memory amount because they have to, but the fact is that is really pointless to have if you want to run a game smothly without any frame degradation, hey, its not that hard to understand. thanks liquidacid and everybody else who posted.

What kind of toxic man-thing is happening now?