Yes, you can play GTA IV in 4GB Ram but only with the following.
GTA IV is not a high graphics card demanding game.
This game needs only 2GB as a minimum.
Even you can play this game with a low-end graphics card.
Which processor will be the best.
Yes, you can play this game with 2gb ram and 4gb ram. But the main thing is you need the following to run properly.
Processor to play GTA 4
The minimum processor which is required to play GTA IV is Intel core 2 Quad Q6600.
You can only play GTA 4 with this processor but it will not run in more than 1080p settings.
To play this game for more than 1080p resolution you need a minimum I3 2100 processor.
And the required processor for GTA 4 to play is I5 3550.
Graphics card to play GTA 4.
Ram to play GTA 4
RAM which is the minimum required play GTA 4 is 2GB. But only for low settings at 1080p resolution.
RAM 2Gb which is required to play GTA IV should not be less than 800Mhz. But if the Ram is less than it will result in a lag in your game.
For playing GTA 4 in 2k settings you need a graphics card under 25000.
RAM which is recommended to play GTA 4 is 8GB.
Why recommended Ram is more it is for 2K gaming experience. This will give you smooth fps if you are playing that game at 2k resolution. But only with the recommended graphics card and processor.