Radeon HD 4650 1GB vs Radeon HD 7770

Intro

Compare those specifications to the Radeon HD 7770, which has a clock frequency of 1000 MHz and a GDDR5 memory speed of 1125 MHz. It also makes use of a 128-bit bus, and uses a 28 nm design. It is comprised of 640 SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 1GB		55 Watts
Radeon HD 7770		80 Watts
	Difference: 25 Watts (45%)

Memory Bandwidth

In theory, the Radeon HD 7770 should be 221% faster than the Radeon HD 4650 1GB in general, because of its higher data rate. (explain)

Radeon HD 7770		72000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 49600 (221%)

Texel Rate

The Radeon HD 7770 is a lot (more or less 108%) more effective at texture filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 20800 (108%)

Pixel Rate

The Radeon HD 7770 should be much (more or less 233%) faster with regards to anti-aliasing than the Radeon HD 4650 1GB, and also capable of handling higher resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon HD 4650 1GB		4800 Mpixels/sec
	Difference: 11200 (233%)

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 data (measured in MB per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total texture units by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one 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 amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.