GeForce GT 640 DDR3 vs Radeon HD 3850 1GB

Intro

The GeForce GT 640 DDR3 uses a 28 nm design. nVidia has set the core frequency at 900 MHz. The DDR3 RAM is set to run at a frequency of 1782 MHz on this particular model. It features 384 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.

Compare all of that to the Radeon HD 3850 1GB, which comes with core clock speeds of 668 MHz on the GPU, and 828 MHz on the 1024 MB of GDDR3 memory. It features 320(64x5) SPUs as well as 16 TAUs and 16 ROPs.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the maximum amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 amount of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel 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 potential to get to the max fill rate.