Based on everything I had read, suggested that SLI didn't work with FSX but since I can't confirm it form personal experience, I'll stand aside. All I know is that based on the ORBX forums with some impressive machines on there, people are all opting for a single powerful, single core GPU. I would be very interested in finding out if by having 5 monitors/projectors, you would get a performance boost by throwing in more video cards rather than upgrading the single unit to a monster to cope with the resolution. With time I'm sure I'll find the answer and I'm sure I read the answer hundreds of times without recognising it but alas. Anyway, the other thing I suggest you do is go to the ORBX forums. You won't be able to view much without signing up but if you do, there's really a lot of information about getting the right hardware for FSX with heaps of other posts related to tweaking it to work just so. To be honest, from what I've seen, it's probably the best single source for this sort of information. I've been on there for a while and over time I've seen peoples setups change and see the subsequent results of the changes and the impression I got was that really what I was saying and Phtat are pretty much gospel when it comes to getting an FSX machine at the present moment. From what I've seen, the new 980X overclcoked to 4.8Ghz is the way to go but that's way out of most peoples price ranges for a computer component so I won't even go there . Sure the 920/930 isn't optimal, mines at 4Ghz I get down to 8fps in some demanding places e.g. Brisbane which is far from your EGLL and De Gaulle so really, we are from what FSX is capable of but at the same time, even further with what current affordable hardware can handle. So really, FSX is a buggy, poor platform which we need changed and hopefully Flight be much more efficient but I'm willing to bet it won't but until that happens, we just need to wait for a few generations of computers to get it running to its full potential. Then again, the next generation of processors will probably concentrate on multicore processing rather than the power of any single core and FSX won't be able to utilise that so really, we need a new platform :P. Anyway, I'm going in circles now, I think to sum up, all I can say is, FSX is a beast that doesn't have a simple answer/magic bullet and you won't be 100% happy with what you get regardless of what it is unfortunately but certainly 1333mhz ram and an i7 with a good over clock are a must. Harddrive wise, I want to see the benefits of solid state first hand but I can say that conventional hard drives aren't quick enough for serious scenery like ORBX but enough for stock FSX scenery.