GeForce 9400 GT 256MB vs GeForce GT 420

Intro

Compare those specs to the GeForce GT 420, which makes use of a 40 nm design. nVidia has set the core frequency at 700 MHz. The GDDR3 RAM works at a frequency of 900 MHz on this particular card. It features 48 SPUs as well as 8 TAUs and 4 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

In theory, the GeForce GT 420 should be much faster than the GeForce 9400 GT 256MB overall. (explain)

GeForce GT 420		28800 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 16000 (125%)

Texel Rate

The GeForce GT 420 is quite a bit (approximately 27%) more effective at texture filtering than the GeForce 9400 GT 256MB. (explain)

GeForce GT 420		5600 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 1200 (27%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the GeForce GT 420 is the winner, by a large margin. (explain)

GeForce GT 420		2800 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 600 (27%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the maximum amount of information (measured in megabytes per second) that can be transferred past the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.