Wite with problems :
ledhead11 :
No problem, I understand.
It might be possible that the RAM usage isn't really the issue. Even though I doubt its a driver issue, many would recommend making sure you have the latest. The only caveat is that if this GPU is old enough, sometimes newer drivers make things worse.
Here's a small list of other things I would look at and I apologize if it starts to feel like a snipe hunt and you'll want to have some utilities on hand to check even if your bios are telling different. CPUz, CrystaldiskInfo, GPUz. Both CPU and GPU z will show a lot of same info but there's a couple of minor differences. These aren't the end all be all of monitoring but they'll work for these purposes.
1. Check your memory settings are they at the right speed for what you know you have. RAM is listed sometimes in the pre-DDR rate(i.e. 1333mhz will show as 667mhz)
2. Disk speeds. Are they matching what they're supposed to be. You really want at least SATA II/300Gb/s or SATA III/600Gb/s
3. GPU PCIe speeds. It would only matter if for some reason its running in PCIe 1.0 x1. PCIe 2.0 x8 or x16 or 3.0 x8 x16 are fine.
4. If any of the above isn't correctly matching what it should then you might need to adjust your BIOS. Be careful if you do.
When you say that others have run better with same or less, please do an exact comparison let me know what the differences are(CPU,RAM,GPU).
Even if you have the same basic equipment, cooling and power can cause issues. If your PSU is even slightly lesser than what those others are using that can cause issues for the GPU. If things are getting too hot the GPU could be throttling.
Is this an NVIDIA card? If so and you've customized things in CP then try resetting everything back to default. I've had issues were maxing the wrong thing fought with the game engine. As much as possible let app's control the settings.
For 'stutters' or even micro-stutters(usually SLI related) there really can be a lot of different causes.
Others have played the game on my same GPU and a weaker CPU and on 4GB or 3GB RAM and got better performance
I understand and that's also why I said it might not really be a RAM issue but as I stated above there's a lot more to it than that. If you're trying to re-create what they did you need to identify exactly what different settings or parts might be on your system vs. theirs. You also need to list all the specs of your system vs the ones you're comparing yourself too.
At this point there's only be a vague reference of what you have and others but nothing truly detailed. Most people who post questions on sites like this will generally list their MOBO(sometimes BIOS version), CPU, GPU(exact model), RAM(size & speed), drive(s), PSU, sometimes cooling and case, OS(type and bit version), sometimes GPU driver version installed, display(type, sometimes connection method, resolution/refresh settings). Gather that info for you along with someone you're trying to compare with and the detail may reveal itself then.
PC gaming is more than just parts, there are a lot of settings that need to be properly calibrated. On, that note, did you try setting a frame cap-say either 30 or 60fps, are you using V-sync or anything similar? Those are also settings that can drastically affect performance. As I also mentioned above, in the GPU settings software(NV CP or AMD Catalystor whatever its called now) set as many things to default/app controlled and only tweak the things in GTA V. This will minimize the amount of conflicts between the two.