An ASUS-made NVIDIA GeForce GTX 760
A stock NVIDIA GeForce GTX 680
A GPU, or Graphics Processing Unit is like a little computer within your computer just for processing images, 3D models and environments, video, anything to do with colors on your screen basically.
VRAM, or Video Random Access Memory is fully responsible for loading up textures from your games, and putting them on the screen for you to see. More VRAM means your game (Skyrim or GTA:IV) has the potential to be modded with higher-resolution textures, at a lower framerate cost. card has a amount of VRAM (Video Random Access Memory) Most cards these days have 2GB of VRAM, although the near future may demand higher.
It's the thing in your computer responsible for allowing high-end graphics, like from games to work smoothly.
There are two manufacturers that make these cards, NVIDIA, and Radeon. Radeon cards are cheap and reliable, and feature Eyefinity technology for multiple monitors, but that's about it. NVIDIA cards feature PhysX, NVIDIA surround, TXAA and FXAA technology, and they're pretty good overclockers.
As for game compatibility, games that show the AMD or NVIDIA logo when you start up the game means almost nothing. When a manufacturer claims the game is "optimized" for that game, it's mostly a marketing thing. Some games utilize NVIDIA PhysX technology, which isn't a scam. Games like Borderlands 2 and Just Cause 2 use PhysX and CUDA technology to add little things like better physics so you can watch that piece of metal fall on the ground like the real deal. Read up on CUDA technology here: https://developer.nvidia.com/what-cuda
I personally like NVIDIA cards made by EVGA or ASUS, they just look and feel nice.
If I had to buy a Radeon card, I'd choose XFX for their cards. They are usually silver and black and the black editions have a dual-fan cooling solution which is really nice.
SLI and Crossfire Technology
Probably one of the biggest topics of conversation of GPUs.
Basically, SLI (for NVIDIA) and Crossfire (for Radeon) is the technology that enables you to connect two, three, or four graphics cards of the same make and model to potentially increase your total graphical power.
When you connect two or more cards, there are some things you should know.
- You can only connect two of the same chipset, you can mix manufacturers, like EVGA, MSI, and ASUS.
* You cannot connect two cards of a different chipset, such as a GTX 660, and a GTX 670.
* Radeon and NVIDIA cards can never be mixed, even if made by the same manufacturer.
There is some controversy behind SLI and Crossfire, that it effectively doubles your GPU power, or that the VRAM adds to each other. I'm going to clear some of that up.
- The VRAM from each card does not add to the next. If you paired up two 2GB cards, you would not had 4GB, you would still have 2GB of VRAM.
- You cannot connect two NVIDIA cards of the same model if they have different VRAM capacities.
- Connecting cards does not effectively double/triple/quadruple your graphical power. The technology is not used very well by a lot of games, and usually using a single card will get you the best performance. In fact, the more cards you connect, the higher chance that you will have microstuttering. This is a thing you definitely do not need to have.
