GoD_OF_GaMiNg

May I also state, you might want to have your motherboard manual handy to explain things. Basically you want to edge up your cpu multiplier 100 mhz at a time until it becomes unstable. You can check for stability by running prime95, or aida 64. Keep an eye on the temps and make sure they aren't spiking. If you find instability, SLOWLY raise and test the cpu voltage. If the stability comes back after raising the voltages, you can try bumping it up more. If you are running into heat issues, I would back it back down. If you want to fix the heat issues basically you want to either get a good 240mm aio water cooler, or delid your cpu, or both. Sometimes asus throws in automatic overclocking profiles in there for you. They might work, they might not.

Games I would play on that... Diablo 3, Dota/LoL, Borderlands, Dungeon Defenders, HL2/CSGO/Garry's Mod/Left4Dead2/(insert source engine game here), Torchlight1/2, WoW, Guildwars 2 maybe (it's free), Quake Live, Battlefield 2-3 (possibly 4?), Doom3 BFG Edition, Elder Scrolls Oblivion/Skyrim (without a ton of graphical mods), Fallout 1-New Vegas, Prototype, Any 2D indie game, emulators (except maybe like the ps3 one, but I'd still try), GTA V might run on low settings pretty good. GTA 1-3, vice city, San Andreas, possibly 4-5 on low settings. Titanfall on low settings, Mass Effect, I'd try overwatch on low settings at like 720p, COD 1, 2, 4 mw, mw2 (if you like those games), too many more to list. The trick is, try to get games from like 1-2 years before the board was released and you should be fine.

Popular games you could play on that are:
Overwatch
World of Warcraft
Fortnite
Dota 2
League of Legends
Rocket League
Minecraft (lol)
Fallout 4 (on low settings?)
 
Lots and lots of old games (2014-2015 and older?)

It'll run RE7 on low settings. You'll need a beefier GPU to run current games at decent detail settings.

I did cut a hole in the sidepanel of my T1000 and put a fan there...

Maybe in a decade we might not need RAM.
 
But for now yes you need both. SSDs are good for gaming.

Yup, they come with either cherry mx reds or browns. Reds push down smooth the whole way, while browns have a little bump when they reach the point of actuation. Everyone has their own preferances though. Personally I like browns

It's not pirating, you can get the ISO from MS directly and not activating Windows 10 doesn't give you a time limit on being unactivated. Totally legal and it's a known trick to save some money on low budget builds.

If you never want to play DX12 titles: Windows 7, other wise Windows 10. Not a lot to it...

That is literally the definition of air cooler. Anything that's not using some sort of liquid is an air cooler. 
Just check the Temps (during load pls) and then we'll see if you need a new cooler or if there's something else wrong. 

That definitely is a bit low score but you don't have the hyperthreading enabled? I've got 476 cb on a W3550 with hyperthreading enabled.

I'd say a score of 332 is definitely below average for desktop processors, however, seeing as how that particular chip launched in 2009 I'd say it is an acceptable score. You can still play games with it, albeit at lower settings, but it will start to age more rapidly due to games starting to take advantage of fast multi core and SMT/Hyper Threaded enabled processors. My i7 6700k for instance scores just shy of 1000 points @ 4.5GHz ( around 970 to be exact. ) However that Xeon should not impose a bottleneck on that 750, and you could probably run a graphics card up to about the GTX 1050 level and still get acceptable performance.