Context: It's the current year and I'm using a desktop computer with Windows XP 32-bit installed, 700GB HDD space, 3.25 GB RAM, an AMD Athlon II X2 245, 2.91 GHz processor, and heaven only knows what GPU, motherboard, PSU and other stuff. The whole thing was built circa 2009, by the household computer whiz, that is, Dad, and he's no longer living with us and it's about fucking time I learned to do it myself anyway. My happiest moments with this PC were: in 2012, when I replaced my PSU with one that didn't BSOD/start the godawful overheating alarm whenever my GPU was required; in 2015, when I upgraded from 2 GB RAM and added an extra 232GB HDD. In some of my uni classes, I had to use Windows 7 and got massively confused. Lots of websites tell me to update my web browser, lots of browsers have become unavailable in the 32-bit version. I've had one utility (downloaded today) refuse to open in the 32-bit version and another barf on me by throwing the Out of Memory Exception which apparently happened because of XP. The point of this rant being, life is hard at the end of the Cretaceous. Most of what I know about computer hardware, I've learned in the past three hours. Until now, I've failed to learn because there was always someone to do it for me. What I need from you guys is to point out incompatibilities between these pieces of hardware, and to answer a couple of questions about the processor and the power source. What I'm going to use it for: some older 3D games, 3D modelling (Autodesk software) and texturing (Photoshop, incl. OpenGL painting on 3D models), mostly on the low-poly side, possibly some CAD work after I graduate. More advanced, resource-intensive uses are unforeseen, but not ruled out. I also have a monster of a modded game which loads a few tens of thousands of downloaded items upon startup, and I need it to do this in less than 3 hours, hence the SSD, I guess. Budget: I'm mostly thinking of buying the components piecemeal, I can't afford to do it all at once. I've come up with two possible builds, one that's mid-range for most usual work and low-ish budget ($850-$1000), and one that mid-to-high range, better suited for professional use (in case I'm going to use it for work a few years from now), and in the $1500-$2000 price range. It should take me about half a year to buy all the stuff, less for the cheaper build. I'd like to keep my current peripherals, I like them. And I really don't give a shit about most other components; maybe considering a UPS, although I might reconsider if it takes up too much space. The More Expensive Build CPU: Intel I7-5820K, 6-core, 3.3GHz/3.6GHz, 15MB, LGA2011-v3 socket Importantly, I don't know whether a 6-core processor is overkill for what I want to do with it. 3D modelling and other software I might use as a future engineer are famously hungry for processing power, and I don't know whether/when I'll move past low-poly 3D modelling. Motherboard: ASUS X99-A/USB 3.1, 2011-v3 socket, 8xDDR4, 8xSATA3, ATX (This is overkill for me, but I noticed that the motherboard I was initially considering had a 1151 socket, lol) GPU: MSI NVIDIA GeForce GTX 970, GTX 970 4GD5T OC, 4GB GDDR5, 256bit SSD: A 480GB, SATA3 one; whichever Extra HDD: A 2TB, 7200RPM, SATA3, 64MB one; whichever RAM: Kingston HyperX Fury 16GB DDR4, 2133 or 2666, should be enough PSU: CORSAIR Builder Series CX750M, CP-9020061, 750W, 120mm, 85% efficiency, modular ... but my local store says this one is out of stock, so, alternatively, one that's double the price and seems overkill: HXi Series HX850i, 850W, 14cm fan, modular, CP-9020073-EU, 92% efficiency I also have no idea how to calculate the power demands of a build. Please help. How power-hungry is this whole thing? The Less Expensive Build CPU: INTEL i5 6400, quad-core, BX80662I56400, 2.7GHz/3.3GHz, 6MB, 1151 socket Motherboard: ASUS Z170-K, 1151 socket, 4xDDR4, 6xSATA3, ATX GPU: ASUS AMD Radeon R9 380, STRIX-R9380-DC2-2GD5-GAMING, 2GB GDDR5, 256bit SSD: A 240GB, SATA3 one, whichever Extra HDD: A 1TB, SATA3 one, whichever RAM: Same PSU: See above For both builds, I haven't searched for a case, for an audio board (I mostly have audio off), for peripherals, network cards, DVD writers and whatever. Also, please tell me whether I need coolers and I haven't included them. I don't plan on overclocking the computer. Also also, if someone could tell me how difficult it is for a non-moronic newbie with internet access to physically assemble all of this without getting angry and starting to jam components into random sockets, I'd appreciate it. So, what do you think?