Is ram very compatible?
I want to make an AMD APU Kaveri (budget) build and need to make sure I get the right motherboard as well. Its been tricky since its new, would all A series motherboard work with this APU?
Yes, ram is fairly compatible. You can mix and match brands, sizes, speeds, and timings. The faster ram will downclock to match the slower ram though.
For the APU you will need an FM2 or FM2+ motherboard.
You need an FM2+ socket motherboard and DDR3 RAM. Here are some motherboards: http://pcpartpicker.com/parts/motherboard/#sort=a8&s=26
I STRONGLY suggest (major performance benefit) that you go with DDR3-1600 or better, since this is your VRAM as well. Possibly consider getting 4GB DDR3-1866 if you were going to get 8GB of slower, that's the optimal speed for these APUs (after which anything faster has diminishing returns) and you can add another 4GB later. If you were only going for 4GB already, make sure you get DDR3-1600 or better.