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: CybertronPC Steel-9600 Gaming Desktop - Liquid-Cooled Intel i7-6700K 4GHz Quad-Core Processor, 16GB DDR4 Memory, NVIDIA GTX960 (2GB GDDR5) Graphics, 2TB HDD, DVD±RW, Windows 10
Product description: Steel yourself for battle with the CybertronPC Steel-9600 TGMSTEEL9602GN Gaming System! With the speed and power of its Liquid-Cooled Intel Core i7-6700k 4.00GHz 4-Core Processor, 16GB of lightning fast DDR4 Memory and unstoppable 2GB NVIDIA GeForce GTX960 Graphics Card, the CybertronPC Steel-9600 delivers performance with an edge. The 2TB Hard Drive can not only house tons of your games, it also provides storage space for your favorite music, movies and all the other bits of your digital life. The CybertronPC Steel-9600 is equipped with a DVDRW optical drive for software installation, data backups and watching your favorite movies. Don't wait - order your CybertronPC Steel-9600 today!
Product feature: System: Liquid-Cooled 6th Gen Intel i7-6700K 4.00GHz 4-Core (4.2GHz Boost) | Z170 | 16GB DDR4-2400 PC4-19200 | 2TB HDD | Genuine Windows 10 64-Bit, Graphics: NVIDIA GeForce GTX 960 2GB GDDR5 | 24X DVDRW Dual-Layer Drive | Audio: 7.1 Channel | Gigabit LAN | Keyboard & Mouse, Expansion Bays/Slots Total(Free): 3(2) Ext. 5.25" | 4(2) Int. 3.5/2.5" | 2(2) PCI | 2(1) PCI-E x1 | 2(1) PCI-E x16 | 4(2) DIMM 288P, Connectivity: 6x USB 3.0 | 2x USB 2.0 | 1x RJ-45 Network Ethernet 10/100/1000 | Audio | 1x DVI | 1x HDMI | 3x Display Port, Chassis: Gaming Mid-Tower w/500 Watt Power Supply | 1 Year Parts & Labor Warranty | Free Lifetime Tech Support, Liquid-Cooled 4.00 GHz Intel Core i7-6700K Quad-Core Processor (Max speed: 4.2 GHz), 16 GB DDR4 Installed Memory, NVIDIA GeForce GTX 960 Graphics w/ 2 GB GDDR5 Memory, 2 TB Serial ATA Hard Drive (7200 RPM, 64 MB Cache), LCD Fan Control Panel, Z170 Motherboard, 500 Watt Low Noise Power Supply, Windows 10 64-Bit Home
Product brand: CybertronPC
Target attributes: Processor Speed
Answer: attribute: processor speed
value: 4.00ghz
source: product feature
attribute: processor speed
value: 4.00ghz
source: product description
attribute: processor speed
value: 4.00 ghz
source: product feature
attribute: processor speed
value: 4ghz
source: product title