GeForce 8400 GS 512MB vs GeForce 9400 GT 256MB

Intro

Compare all of that to the GeForce 9400 GT 256MB, which has GPU clock speed of 550 MHz, and 256 MB of GDDR2 memory set to run at 400 MHz through a 128-bit bus. It also features 16 Stream Processors, 8 Texture Address Units, and 4 Raster Operation Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8400 GS 512MB		40 Watts
GeForce 9400 GT 256MB		50 Watts
	Difference: 10 Watts (25%)

Memory Bandwidth

The GeForce 9400 GT 256MB, in theory, should be quite a bit faster than the GeForce 8400 GS 512MB in general. (explain)

GeForce 9400 GT 256MB		12800 MB/sec
GeForce 8400 GS 512MB		6400 MB/sec
	Difference: 6400 (100%)

Texel Rate

The GeForce 8400 GS 512MB should be just a bit (more or less 18%) faster with regards to texture filtering than the GeForce 9400 GT 256MB. (explain)

GeForce 8400 GS 512MB		5200 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 800 (18%)

Pixel Rate

The GeForce 8400 GS 512MB should be a small bit (about 18%) better at anti-aliasing than the GeForce 9400 GT 256MB, and will be able to handle higher resolutions while still performing well. (explain)

GeForce 8400 GS 512MB		2600 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 400 (18%)

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: Bandwidth is the max amount of data (counted in MB per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the card's interface width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the graphics 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 number of pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.