Prebuilt computers that are windows based are cheapr for a reason. Never should someone that knows how to build go out and spend money on prebuilt. As you get crappy parts that are all low end.
What one can buy in store i can build it with better components all name brand with warranties, windows installed for around 30-50% cheaper.
My last build cost close to 2k. Store bought one of this caliber would be over 4k in store and im sure would be low end Ram, Motherboard,Hard drive,Heatsink, and so on.
Its ALWAYS best to build your own computer saves time, money and you know what goes wrong if something does. Then send it out for repair rather Whole computer to Hp,Dell,Gateway .....
To the OP you can build one and put Apple OS on it. Ive done it for college class through a Virtual Machine off my Desktop.