Hello. I am going to build a new comp. Getting Vista 64bit. Its going to be a budget AMD build. with a single 3850.
I will do light gaming.
At most at one time I would be running: internet, poker, music, and something else.
Do I REALLY need 4gb to have a smooth operation with the 64 bit? Or will 2 GB be plenty?
Will I take a performance hit during gaming?
During what computing situation is that extra 2GB going to help out the most?
4GB is worth it - even on a 32-bit Windows XP system.
Even if you don't use all of your memory, it makes for a very large disk cache and you can disable your pagefile. Software and games that you launched yesterday, will launch much faster even if you've done an overnight virus scan or disk defrag since that time.
You can launch many applications, then launch applications you launched yesterday -- the application will load much faster because it's still in your disk cache 24 hours later. Even if you've ran a videogame or big apps such as Adobe Photoshop or Visual Studio since that time, or even an overnight virus scan. Even if you use up less than 1 gigabyte of memory in "Task Manager" - you still have a 2.5 gigabyte disk cache that provides massive application launch acceleration (and game acceleration too -- loading savegames in videogames is much faster, for example. A savegame that you saved earlier today, quit the game, did your homework or Visual Studio, then you load the game, the savegame still loads fast - because it's all still in your disk cache). Oh, and then you quit the game again, you load your Word/Photoshop/Visual Studio/etc and it still loads up pretty fast as if you never launched a videogame.
In fact, the general performance improvement of having 4GB DDR2 outweights spending the same amount of money on 2GB of DDR3, so if you're making a decision between DDR2 or DDR3 of the same price, get 4GB instead of 2GB even if you only get DDR2.
There is inefficiency on 32-bit systems where you can only access 3 or 3.5GB of memory. A 32-bit system can only access up to 4GB of memory (main + GPU memory), and so if your video card is 512MB, Windows XP 32-bit will only be able to access 3.5 gigabytes of your 4 gigabytes. But it's still worth it having 4GB in a current system, considering how cheap memory has become.