A graphics card takes the load of processing 3D graphics off your CPU.
The GeForce 4 MX series is an obsolete line of computer video cards released by Nvidia in 2006. Each card has an integrated DVI digital video connector and an S-video tc-out connector. They connect to the AGP slot on your motherboard, an upgrade from older video cards that used a PCI slot. Nvidia makes graphics acceleration technology, not the cards themselves, so the details of the architecture will vary from card to card, but the essentials are identical.
GeForce 4 MX 420
The MX 420 is the bottom of the GeForce 4 MX line. It has a 250 MHz processor core and 64 MB of RAM. The memory is 166 MHz SDR memory, with a 128 bit bus. Like the other GeForce 4 MX cards, it does not support pixel shaders. The GeForce 4 MX line supports the OpenGL version 1.3 and DirectX version 8.1 3D graphics libraries.
GeForce 4 MX 440
The mid-range card of the GeForce 4 MX line, the MX 440 has a 270 MHz core processor and 64 MB of memory. While every GeForce 4 MX card has 64 MB of memory, the MX 440 uses 200 MHz DDR memory, as opposed to the slower SDR memory used in the MX 420.
GeForce 4 MX 460
The MX 460 is the fastest GeForce 4 MX graphics card. It has a 300 MHz processor and 64 MB of 200 MHz DDR memory. The amount of memory is the same in all three cards, but the MX 460 uses faster memory than the MX 440 and 420. All three cards use the same underlying technology and support the same 3D graphics protocols, as mentioned above.