[Build Help] Adding more RAM, need some info

I have this kit of RAM (2x4GB, CAS10, 1866MHz) and I need another 8GB because After Effects is running incredibly slow even when it's the only thing open.

I know I need more RAM from having similar issues in Photoshop and fixing it by closing some things but AE needs so mch more RAM. I just don't remember as much as I did a year ago about computer parts. I don't know what specs need to match up for the best experience other than needing dual channel. Am I fine with any CAS, MHz and brand? Ideally I would buy this or this since I would like black heatspreaders but if I have to match CAS and MHz then I'd just buy another set of my original RAM which is $10 more.

My current build is as follows. Not sure if it might mean anything in regards to what RAM I can get.

PCPartPicker part list / Price breakdown by merchant

Type	Item	Price
CPU	Intel Core i5-4430 3.0GHz Quad-Core Processor	Purchased For $110.00
Motherboard	ASRock Z87 Extreme4 ATX LGA1150 Motherboard	Purchased For $125.00
Memory	Kingston Fury Black Series 8GB (2 x 4GB) DDR3-1866 Memory	Purchased For $0.00
Storage	PNY XLR8 120GB 2.5" Solid State Drive	Purchased For $45.00
Storage	Kingston HyperX 3K 240GB 2.5" Solid State Drive	Purchased For $0.00
Storage	Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive	Purchased For $90.00
Case	Fractal Design Arc Midi R2 (Black) ATX Mid Tower Case	Purchased For $115.00
Power Supply	XFX 550W 80+ Bronze Certified ATX Power Supply	Purchased For $25.00
Case Fan	Cooler Master SickleFlow 69.7 CFM 120mm Fan	Purchased For $3.00
Case Fan	Cooler Master SickleFlow 69.7 CFM 120mm Fan	Purchased For $8.00
Other	PNY GTX 660 Ti	Purchased For $130.00
Other	Ralink RT5370 USB WiFi Adapter	Purchased For $15.00
Prices include shipping, taxes, rebates, and discounts
Total	$666.00
Generated by PCPartPicker 2015-04-07 05:43 EDT-0400