Computer building questions?

[Azazel]

I'm in the Army and looking at a deployment to Afghanistan in the near future which gives me the chance to save a years worth of pay tax free (probably the only perk involved with being in the infantry overseas). Point being, I'll get back and then I'm planning on spending a chunk of that on a new system. I'm planning on building it from scratch rather then paying the extra doug on a Dell, Falcon, Alienware, etc. My questions are:

1. How do you run two GPUs at once? Is it as simple as just plugging them in? Or is there software/bios wizardry required?
2. Will all sims/games take advantage of two GPUs once they're set up?
3. Do you need liquid cooling honestly, or is that only if you're overclocking the CPU?
4. Do motherboards come with a bios already on them or do you have to install it? If so, how?

I've been a flight sim nut since "Chuck Yeager's Air Combat" when I was 10, oh heady days. However, I've been out the air for about 3 years now due to work and my last deployment to Iraq. My last computer was one from college and finally gave up the ghost last year. Anyways, I'm looking forward to taking a year off when I get out and doing nothing but goof off, build a new rig, play some new flight sims and I will only rejoin society once my lust for slacking off and flight simming has been forefilled (this will never happen of course). I've learned that getting shot at on the computer is much more enjoyable then in real life, who knew right? Anyways, any help for those comp question would be much appreciated.

Azazel

[Frederf]

1. Two GPUs is known as SLi (nVidia) or Crossfire (ATi). Running two video cards is a pretty straightforward affair. You'll need a motherboard that handles the task (check Crossfire vs SLi enabled), two identical video cards, perhaps a few extra power connections, and sometimes a physical bridge that goes between the two cards (will come with). Any BIOS options for single/dual graphics cards will be simple enough. Many boards are strictly hardware dip switches and jumpers to enable SLi/Crossfire. The nicer ones put the option in the BIOS.

When it comes to dual video cards you want to really pay attention to what your PSU can output not only in terms of watts (easily 100W per card) but also the concept of "rails" for power, how independent they are, and if there are the proper supplemental power connectors for the cards.

2. Two GPUs is a motherboard/OS level thing, so as far as the games go all games will perform better on two cards as opposed to one. Some software is optimized for dual cards however.

3. Liquid cooling is not necessary for the most part. A good case with good airflow and good cable management will handle a powerful computer just fine. Video cards are power and heat monsters, often outstripping the power/heat needs of the CPU, so I won't lie. You just want to make sure your cooling is adequate.

4. Motherboards come with a BIOS.

Normally I avoid SLi/Crossfire just because it can have some compatibility issues, have steep power/heat requirements, but for flight simming it's not a bad option. You get more pixel pushing power and double the video memory, good things in most flight sims.

[Azazel]

Thanks,
That helps me a lot actually. I'd like to make a top end system but I've been out of messing with computer hardware for a few years so I'm doing my best not to end up completely baffeled by the new gear out there. I'm still a year or so from building this but I get excited just thinking about it.