I optimized my computer, then did some very minor changes to the fsx.cfg file. Then the horror: the scenery was "tearing" in the middle of the screen. I set vsync ON through Nvidia's control panel, and it worked! (I am controlling the sim's graphics through the sim otherwise.)
With fairly demanding settings, I'm getting 50-60 FPS with Captain Sim's 7-Series. (That's with no traffic, but still...) It is smooth as glass. Alienware has a neat way of shutting down unnecessary stuff when you launch a game. (Yes, I know there are programs for that.) The profile even includes the mood colors on the computer lol -- the ultimate frivolity! Still, it does look cool. I may use it in court

I researched the old fixes for sound and electrical problems. But when I loaded the 757, there was blessed SILENCE. No "phantom engines." Moreover, the cockpit sounds all worked perfectly. I did not do a full flight yet, but those are the kind of niggling little things that drive people crazy about Captain Sim... and they appear to be fixed.
Same with the 767. Bravo.
But it was the 777 that was jaw-dropping. The virtual cockpits in the 757 and 767 were true works of art. But the 777 was just so crisp it was a joy to behold. I could not resist taking off just to see one of these birds in the air. It was a pretty harrowing experience for the passengers, but a joy for me.
Best of all, I am remembering more than I thought I did. I started the 757 from the APU and managed to get both engines running. All from memory. I even told the stewardess how much I have missed her... my wife looked up from her knitting at that one.
So if you've stuck around, improvements might seem too slow. But if you're coming back after two years absence, you can notice a big improvement.
So the 757 will be the first airplane I start to work on. The Captain Sim 757 and I go way back... I wrote the AVSIM review for her. (And the 767.)
The only negative is the livery section has far too many dead links now. One of my favorites -- the Avianca 757 by Jadethar is gone, as are most (all?) of the McPhat freebies. Now you get taken to their website and I did not find Captain Sim among their free airplanes. It looks like we no longer have any South American liveries.
But I am feeling very positive about Captain Sim at the moment. I know gremlins may lurk within the FMC, (I remember wrestling with the TD bug back when I was active before, and it still seems to be around.)
Even my dog is a Captain Sim fan. Back when I worked for the state (the job I lost) I had to live in an apartment in a different city than my wife. But I had my yorkie Buster. I spent a LOT of time simming back then (just me and Buster... not much else to do). When he heard the familiar sequence of sounds signaling engine start-up, he came over and sat next to me, looking at the laptop. (Of course he may have been mesmerized by the subtly changing mood lighting.)
I don't have the free time I used to. I have a criminal defense practice and am a grad student (theology). But I'm looking forward to getting reacquainted with these wonderful works of art created out of programming code (and the contributions of a talented community of painters).