I have an HP Compaq pro 6005 SFF that I recently purchased, and was wondering if i would be able to upgrade it to my liking, it has 2 GB of DDR3-1066 RAM, a crappy AMD Sempron 145 single core CPU and AMD HD 4200U integrated graphics, I was wondering if I could install 16 GB of DDR3-1866 RAM, an AMD Athlon II X4 640, and an AMD Radeon HD6450 2 GB card? if so, what could I put in that is better? it has the typical 240W PSU and no way to upgrade it, I need something that can run reliably for hours on end, and won't need a lot of replacement parts down the road, as I plan to do some gaming and streaming as a YouTuber or twitch streamer, I've done research, and people are saying that it can support DDR4 RAM, but am unsure of it, as it doesn't appear to be new enough. any advice would be greatly appreciated, as I don't like to mix AMD & nVidia products, but I can do it of it is necessary or if the system is already built.