GeForce GT 640 DDR3 vs Radeon HD 7970

Intro

Compare those specs to the Radeon HD 7970, which features clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 7970		8225 points
GeForce GT 640 DDR3		1560 points
	Difference: 6665 (427%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7970		250 Watts
	Difference: 185 Watts (285%)

Memory Bandwidth

Performance-wise, the Radeon HD 7970 should in theory be quite a bit better than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 7970		264000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 206976 (363%)

Texel Rate

The Radeon HD 7970 should be quite a bit (more or less 311%) better at texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7970		118400 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 89600 (311%)

Pixel Rate

The Radeon HD 7970 will be a lot (more or less 106%) more effective at anti-aliasing than the GeForce GT 640 DDR3, and also should be capable of handling higher screen resolutions more effectively. (explain)

Radeon HD 7970		29600 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 15200 (106%)

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 maximum amount of information (measured in MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends 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.