Radeon HD 4650 1GB vs Radeon HD 7750

Intro

Compare that to the Radeon HD 7750, which uses a 28 nm design. ATi has clocked the core frequency at 800 MHz. The GDDR5 RAM runs at a speed of 1125 MHz on this particular model. It features 512 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Both cards have the same power consumption.

Memory Bandwidth

Performance-wise, the Radeon HD 7750 should in theory be much superior to the Radeon HD 4650 1GB in general. (explain)

Radeon HD 7750		72000 MB/sec
Radeon HD 4650 1GB		22400 MB/sec
	Difference: 49600 (221%)

Texel Rate

The Radeon HD 7750 should be much (about 33%) better at texture filtering than the Radeon HD 4650 1GB. (explain)

Radeon HD 7750		25600 Mtexels/sec
Radeon HD 4650 1GB		19200 Mtexels/sec
	Difference: 6400 (33%)

Pixel Rate

The Radeon HD 7750 will be a lot (about 167%) better at full screen anti-aliasing than the Radeon HD 4650 1GB, and also will be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 7750		12800 Mpixels/sec
Radeon HD 4650 1GB		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: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, 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 amount of pixels the video card could possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.