- Rendering Pipelines: 2
- Texture Units/Pipeline: 2
- Core Clock: 200 MHz
- Fillrate: 400 Megapixels/second
- Texture Rate: 800 Megatexels/second
- T&L Unit: Yes
- Memory Interface: 64-bit DDR or 128-bit SDR
- Memory Clock: 166-200 MHz
- Memory Bandwidth: 2.7-3.2 GB/s
- Process: 0.18um
Like the original GeForce 2 MX, the MX 400 features only two of the GeForce 2 GTS’s four rendering pipelines. Similarly, each of the two pixel pipelines features two texture units. The MX 400 does receive a bump in clockspeed versus its predecessor, though, up to 200 MHz. That makes for a fillrate of about 400 Mpixels/s (200MHz x 2 Pixels), and a texture rate of 800 Mtexels/s (200MHz x 2 Pixels x 2 Texels/Pixel). Those figures are precisely half those of the GeForce 2 GTS.
However, any increase in core frequency shouldn’t be taken too seriously, as the GeForce 2 MX is severely bottlenecked by memory bandwidth, as has been demonstrated numerous times. And like the original MX, the MX 400 remains handicapped by the same half-speed memory bus. The MX 400 is compatible with only a 64-bit DDR or 128-bit SDR memory interface, instead of the GeForce 2 GTS’s 128-bit DDR interface. While theoretically the two offer the same amount of bandwidth, a 128-bit SDR interface is considerably more efficient, and will delivery more bandwidth in most cases, so if shopping for an MX card, look for 128-bit SDR rather than 64-bit DDR.
The memory clock of the MX 400 will be slightly higher, in most cases. nVidia seems willing to tolerate anything in the 166 to 200 MHz range, so you can expect to see a variety of different speeds on the market. Obviously, the higher, the better. At 200 MHz, we’re looking at about 3.2 GB/s worth of bandwidth (200MHz x 128-bit x 1/8 bytes/bit), whereas at 166 MHz we’re looking at less than 2.7 GB/s (166MHz x 128-bit x 1/8 bits/byte).
