GeForce GT 315 vs Radeon HD 7770

Intro

Compare those specifications to the Radeon HD 7770, which features a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit bus, and makes use of a 28 nm design. It is comprised of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 315		52 Watts
Radeon HD 7770		80 Watts
	Difference: 28 Watts (54%)

Memory Bandwidth

In theory, the Radeon HD 7770 should be 185% faster than the GeForce GT 315 overall, because of its greater data rate. (explain)

Radeon HD 7770		72000 MB/sec
GeForce GT 315		25280 MB/sec
	Difference: 46720 (185%)

Texel Rate

The Radeon HD 7770 should be much (about 300%) better at AF than the GeForce GT 315. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce GT 315		10000 Mtexels/sec
	Difference: 30000 (300%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7770 is the winner, and very much so. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce GT 315		5000 Mpixels/sec
	Difference: 11000 (220%)

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 information (counted in megabytes per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.