Sys-Nooby :
This is my first time trying to build a desktop, preferably one that can play games on high settings and I don't have much knowledge on computers or what parts are best/needed.
I'm in UK so probably not much point posting a parts list, but essentially things you should consider if gaming is your goal:
- Be sure to put as much money as possible into the graphics card, on that budget you can probably stretch as far as $300, as a good graphics card will give best performance boost in most games (depends on the game though). The upcoming Radeon RX480 looks like a nice option for this price range (we'll get reviews and availability at the end of june, price is supposed to only be $200 for base model). If you want to buy sooner than that, currently the nVidia GTX 970 is a nice card if you can find one for the price. Also the R9 380 and R9 390 cards are worth a look (the latter uses rather a lot of power though so you might have to spend a bit more on your PSU if you want to go that way).
- You also need a decent mid range cpu that has at least 4 cores. Most game builds are around a Core i5 such as the 6500 or 6600k (the latter costs a bit more and gives you the option to 'over clock' it down the line for a performance boost, if you don't want to risk that then the 6500 is probably better value).
- You'll want at least 8gb of ram, and assuming you're going for a 6xxx cpu you'll need ddr4. Some people recomend 16gb of ram, all I'd say is generally you don't need that much right now- although it's true it's likely to become more common for games to need that much in the future.
- Make sure you get a good quality power supply. Avoid high wattage but cheap 'OEM' or 'Unbranded' supplies, when it comes to power supplies you get what you pay for. A nice 500W EVGA unit for $70 will last a lot longer and give more usable power than an 'OEM 1200W' that is being sold for $30.
- Cooling, make sure to get a roomy case and maybe include a couple of extra case fans, as if any of your components overheat they'll throttle back which will kill game performance. I'd personally avoid small compact cases if possible- they look nice and can work well but you need to be very careful about cooling. A nice mid tower case with plenty of vents should be much simpler.