Radeon HD 4650 512MB vs Radeon HD 6750 1GB

Intro

Compare those specs to the Radeon HD 6750 1GB, which comes with core speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 720 SPUs along with 36 TAUs and 16 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 6750 1GB		86 Watts
	Difference: 31 Watts (56%)

Memory Bandwidth

The Radeon HD 6750 1GB should in theory be much faster than the Radeon HD 4650 512MB overall. (explain)

Radeon HD 6750 1GB		64000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 48000 (300%)

Texel Rate

The Radeon HD 6750 1GB is quite a bit (more or less 36%) better at texture filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 6750 1GB		26100 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 6900 (36%)

Pixel Rate

The Radeon HD 6750 1GB is a lot (about 142%) more effective at full screen anti-aliasing than the Radeon HD 4650 512MB, and also will be capable of handling higher resolutions while still performing well. (explain)

Radeon HD 6750 1GB		11600 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 6800 (142%)

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 data (counted in MB per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory in one 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 - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.