You'll have some performance increase, definitely. Since Windows itself will have more free RAM, there won't be as much shoving around for the game to do to grab its required memory, assuming you have a 64-bit OS.
It all depends on how much you've got running in the background. If you have nothing else open and most of the 4GB is free, then you probably won't notice. If you keep programs open in the background such as internet browsers, communication programs, etc then that'll be where the noticeable improvements come in.
thanx sky for a very informative response. i do have Win7 64-Bit with 8gig DDR3 RAM hence my query because i'm always in a process of learning. frequently find myself asking y. i notice that all games and other software etc. by default choose to install in Program Files(x86). gives me the impression that most game developers and software developers seem slow to embrace x64 based OS/hardware. wonder y?
Also with more memory, the less the kernel will have to use the pagefile to store/retrieve system files.
And if games allow the use of extra memory, it can store information so games like Gothic 3, soon to be released Dungeon Siege 3 will seem to flow better.
As for booting up, it may take a few seconds longer due to the fact Windows is loading more system files resident to the memory to be used. So in essence when using your PC it should run a bit quicker.
so its basically to give u more leg room when u're running heavy games and not because its actually needed. most games i see even with their recommended system specs state system requirement somewhere between 3-4gigs. i haven't come across anyone wanting more than that. as to my query regarding almost every game developer and most software developers slow in embracing x64 based OS/hardware. y is that?
The thing about games and programs is they only ever give minimum and recommended specs. Some old games actually gave the specs required for best performance. So even if you meet the recommended requirements, it'll still be able to use more if you have it.
As for not embracing 64-bit architecture... well, I can't speak from experience or knowledge, but I have a feeling that most games never require more specs than a 32-bit system could offer... so really there's not much demand for 64-bit in games. To be honest I've never noticed much difference between the two with the rare game which caters to both. Like I said, though, that's more opinion than fact.
[Edited by Skyheart, 5/15/2011 1:05:26 PM]
u're right. 64-bit offers way more addresses than 32-bit hence the ability of 64-bit systems being able to handle more RAM. most games don't really require those many addresses in 64-bit systems which is y i guess game developers don't make games to specifically run on 64-bit. but i guess in a few years the shift will happen eventually phasing out 32-bit.