1. I see, so your room is the issue here. Unfortunately, all the heat the computer produces will still have to go somewhere - a decent heatsink keeps the CPU running cooler, but the heat from the computer still goes into your room. Undervolting isn't nearly as common or popular as overclocking, and it's worth noting that although motherboards allow you to change voltage, usually it's to
increase voltage, not
decrease it, so different manufacturers will have different available ranges for setting core voltage. For example, this article by Hardware Luxx mentions that MSI and Asus offer different ranges of allowable voltage settings.
Only specific motherboards like
some higher end Asus models offer BIOS flashing without a CPU. In every other case, you'd be screwed and unable to use the computer unless you didn't mind returning or exchanging the motherboard, or had an older but compatible Intel CPU to borrow so you could update the BIOS. Sometimes they do sell H81/B85 motherboards with later BIOS versions so they can support the latest processors out of the box, but unless you can confirm from the store selling the motherboard what revision you're getting, it's a gamble to go with an older motherboard. Some manufacturers do print the BIOS version of the motherboard on the outside box, others don't.
2. There are other options now that I know you don't want the ability to overclock. Features like speedstep will keep processors running quiet and cool when not being worked, and there are low power processors suitable for your needs that will ramp up performance to be close if not the same as the i7 4790.
3. On a budget, the N200 is a pretty decent case to buy. Spend a little extra on some fans (optional extra: hardware fan controller) and you're set. Some motherboards have better fan control than others, Asus is notable for having a decent fan software utility, but other manufacturers also have their own options.
4. There are cases with the plugs the way you want (
Antec Centurion 5, no longer sold), they are just older, discontinued, rare, more expensive, and/or larger than the CM N200. I know you chose an mATX motherboard and case, but are you OK with ATX size?
5. Well, speaking generally most decent SSDs are already a great improvement over hard drives. Something cheap like the
120GB Kingston V300 is about $65 CAD, a little more maybe. Previous generation midrange 120/128GB SSDs are available for $80~90, like the
Crucial MX100.
Cloning drives is easy enough, there are many guides and free software available, like
this.
Still, the 4770S is pretty attractive considering the TDP. Almost 20W difference, which is a lot of heat.
