Radeon HD 4650 512MB vs Radeon HD 7750

Intro

Compare those specs to the Radeon HD 7750, which features GPU clock speed of 800 MHz, and 1024 MB of GDDR5 memory running at 1125 MHz through a 128-bit bus. It also is made up of 512 Stream Processors, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

In theory, the Radeon HD 7750 is 350% faster than the Radeon HD 4650 512MB overall, due to its higher data rate. (explain)

Radeon HD 7750		72000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 56000 (350%)

Texel Rate

The Radeon HD 7750 should be much (about 33%) faster with regards to anisotropic filtering than the Radeon HD 4650 512MB. (explain)

Radeon HD 7750		25600 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 6400 (33%)

Pixel Rate

The Radeon HD 7750 is quite a bit (about 167%) better at AA than the Radeon HD 4650 512MB, and will be able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7750		12800 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 8000 (167%)

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 maximum amount of information (in units of megabytes per second) that can be transported past the external memory interface within a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total texture units of the card by the core clock 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 processed in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of 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 rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.