Radeon HD 4870 1GB vs Radeon HD 7750

Intro

Compare all of that to the Radeon HD 7750, which features a core clock speed of 800 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit memory bus, and makes use of a 28 nm design. It features 512 SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7750		55 Watts
Radeon HD 4870 1GB		150 Watts
	Difference: 95 Watts (173%)

Memory Bandwidth

The Radeon HD 4870 1GB should theoretically perform quite a bit faster than the Radeon HD 7750 overall. (explain)

Radeon HD 4870 1GB		115200 MB/sec
Radeon HD 7750		72000 MB/sec
	Difference: 43200 (60%)

Texel Rate

The Radeon HD 4870 1GB is a bit (about 17%) better at anisotropic filtering than the Radeon HD 7750. (explain)

Radeon HD 4870 1GB		30000 Mtexels/sec
Radeon HD 7750		25600 Mtexels/sec
	Difference: 4400 (17%)

Pixel Rate

The Radeon HD 7750 should be a bit (more or less 7%) better at full screen anti-aliasing than the Radeon HD 4870 1GB, and will be able to handle higher screen resolutions without losing too much performance. (explain)

Radeon HD 7750		12800 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 800 (7%)

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: Memory bandwidth is the max amount of information (measured in MB per second) that can be transferred across the external memory interface within a second. It's worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better 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 can be processed per second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, 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 the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.