Radeon HD 4650 512MB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which has a core clock frequency of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also makes use of a 384-bit bus, and uses a 28 nm design. It is comprised of 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4650 512MB		55 Watts
Radeon HD 7990		375 Watts
	Difference: 320 Watts (582%)

Memory Bandwidth

In theory, the Radeon HD 7990 should be 3500% faster than the Radeon HD 4650 512MB overall, due to its higher data rate. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4650 512MB		16000 MB/sec
	Difference: 560000 (3500%)

Texel Rate

The Radeon HD 7990 is quite a bit (approximately 1167%) faster with regards to AF than the Radeon HD 4650 512MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4650 512MB		19200 Mtexels/sec
	Difference: 224000 (1167%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7990 is a better choice, by a large margin. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4650 512MB		4800 Mpixels/sec
	Difference: 56000 (1167%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of information (in units of MB per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 applied in one second. This figure is worked out by multiplying the total 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 applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.