GeForce GT 640 DDR3 vs Radeon HD 4670 1GB

Intro

Compare all of that to the Radeon HD 4670 1GB, which comes with a core clock frequency of 750 MHz and a GDDR4/GDDR3/DDR3/DDR2 memory speed of 1100 MHz. It also makes use of a 128-bit memory bus, and uses a 55 nm design. It features 320(64x5) SPUs, 32 TAUs, and 8 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 4670 1GB		70 Watts
	Difference: 5 Watts (8%)

Memory Bandwidth

Performance-wise, the GeForce GT 640 DDR3 should theoretically be quite a bit better than the Radeon HD 4670 1GB in general. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 4670 1GB		35200 MB/sec
	Difference: 21824 (62%)

Texel Rate

The GeForce GT 640 DDR3 is just a bit (more or less 20%) better at anisotropic filtering than the Radeon HD 4670 1GB. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 4670 1GB		24000 Mtexels/sec
	Difference: 4800 (20%)

Pixel Rate

If running with a high resolution is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 4670 1GB, by far. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 4670 1GB		6000 Mpixels/sec
	Difference: 8400 (140%)

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 (in units of MB per second) that can be moved across the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is calculated 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core 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 memory bandwidth is, the lower the potential to reach the maximum fill rate.