None of these are new, I'm just happy. Three years ago this month, I built a computer using recommendations from this and other fora. Including later upgrades, it cost about $1,500. I'm sure you could build something better AND cheaper now. Here are my current specs, after several upgrades: Core2Quad Q6600 running at stock speed of 2.4 GHz, 4 gb RAM, Nvidia 8800GT (512 mb). Since building this three years ago I've been running FSX at around 20 fps with pretty high graphics settings. The biggest upgrade (in settings, not fps) was moving from a cheap Nvidia 7600GS to a (now) cheap 8800GT; and from a Core2Duo to a Core2Quad at the same clock speed (didn't improve framerates, but does help a LOT with blurry textures; great for photoscenery).
I've been saving for a new box, but that's still a ways off. I'm cautious with money, and I'm waiting for reasonable prices on chips that I don't have to OC. (Not ruling that out, but see "cautious" above.) Meanwhile, starting a couple months ago, I've seen some big improvements through software:
1. Upgrading from Windows XP (32 bit) to Windows 7 (64 bit). Finally, my rig is taking fully advantage of the RAM I bought two years ago. Right away I noticed smoother turns in the sim.
2. Upgrading the OS also unlocked something I tried earlier but ended up not using because it would kill my antialiasing (AA). This is the Russian light bloom plugin that we discussed here, http://www.sim-outhouse.com/sohforum...ad.php?t=27170, and in the threads linked there. On my 32-bit XP, I could see the effect but after awhile I seemed to run out of memory; the sim wouldn't crash but the lines would get jaggy until I restarted the sim. I thought about buying a video card with more RAM. Turns out, though, I got the same effect by upgrading the OS.
3. FPS_Limiter. This is something I've just recently been playing with. Result so far: whereas I use to lock frames at 20 fps, I'm now locking at 30 for most types of flight. Twenty is fine, but thirty is noticeably more fluid. Maybe it won't last, maybe I'll discover that it's not stable or image quality suffers. Meanwhile I'm having fun: see http://forums1.avsim.net/index.php?showtopic=270347 and http://forums1.avsim.net/index.php?showtopic=245251 for how to set it up.
These are, and aren't, freebies. Upgrading to Windows 7 costs money, even if you don't change any hardware. (I bought a new hard disk so that I could dual boot with my XP setup.) It's also a big investment in time. The other two are free but, again, there's an investment in time. (One way to save some time with the Russian light bloom: use Koorby's configuration, which you can find in the above links).
#4 would, and might someday be, DX10. I couldn't use it before, because I was running XP. I did try it once, just after upgrading to W7, but I was put off by poor antialiasing. Maybe I'll get over that, or maybe someone will find a solution.