GeForce 9400 GT 256MB vs Radeon HD 7850

Intro

Compare all that to the Radeon HD 7850, which has a clock speed of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It features 1024 SPUs, 64 Texture Address Units, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 9400 GT 256MB		50 Watts
Radeon HD 7850		130 Watts
	Difference: 80 Watts (160%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7850 is 1100% quicker than the GeForce 9400 GT 256MB in general, due to its higher data rate. (explain)

Radeon HD 7850		153600 MB/sec
GeForce 9400 GT 256MB		12800 MB/sec
	Difference: 140800 (1100%)

Texel Rate

The Radeon HD 7850 is quite a bit (more or less 1151%) faster with regards to AF than the GeForce 9400 GT 256MB. (explain)

Radeon HD 7850		55040 Mtexels/sec
GeForce 9400 GT 256MB		4400 Mtexels/sec
	Difference: 50640 (1151%)

Pixel Rate

The Radeon HD 7850 will be a lot (approximately 1151%) faster with regards to anti-aliasing than the GeForce 9400 GT 256MB, and will be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7850		27520 Mpixels/sec
GeForce 9400 GT 256MB		2200 Mpixels/sec
	Difference: 25320 (1151%)

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 largest amount of data (counted in MB per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

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