Instruction: First, identify the target attributes from the provided list. Then, scan the product title, description, feature, and brand to extract the values associated with each target attribute. Finally, create a list of dictionaries, each containing the extracted attribute, its corresponding value, and the source where it was found.

Input:
Product title: Sapphire Radeon X1950PRO 512MB 256-bit GDDR3 PCI Express x 16 HDCP Ready CrossFire Supported Video Card 2PORT Dvi-i Tv Out
Product description: Sapphire X1950Pro 512MB 100196L ATi Radeon PCI-Express X16 Video Card with CrossFire Ready, Dual DVI, VGA, HDTV, TV-Out.
Product feature: Engine Clock: 580 MHz, Video Memory: 512MB GDDR3,, Max. Resolution: 2560 x 1600, Memory Clock: 1.4 GHz, Connectors: Dual DVI (Support Dual VGA); TV-out (HDTV ready)
Product brand: Sapphire Technology
Target attributes: Slot Size
Answer: attribute: slot size
value: None
source: None