you wouldnt be saying that if you were trying to land a plane on 10 fps Harold! FPS is very important! besides the smoother it is the more real it feels... *sob* i want more fps!
FPS is not
very important but indeed, 10 FPS is not a lot. But what I meant is that you'll need very good eyes to see the difference between 30 and 40 FPS ...
Typically, you'd want a nice and crisp looking sim and not a lot of FPS. I would not push FS9 to it's limits, but try and lock it at 20-25 FPS, and have a little reserve for what else the sim wants to do. I see a lot of nice shots in here but a lot also have blurried ground textures, which
I don't think is necessary ...
If you're on 'unlimited' the sim will try to get as much FPS as possible. If you lock to a lower value then you will give the sim some breathing room to work on building (for example) ground textures or clouds.
I know my sim can do 40 FPS but I lock it at 30 which is 25% lower than what it
can do. I have a very smooth sim when flying in Alaska, but when I get to a busy airport with a lot of traffic and animations (like PANC with Elmendorf just around the corner) my frames also drop to 'hardly acceptable'. I too get dips to 10 FPS but luckily not very often

Look at my system specs in my sig and you'll see that I don't have a very modern, state of the art high performance machine, although it was when I bought it three and a half years ago. Sure, it has a lot of RAM and a fast hard disk drive but it doesn't have a fast dual core processor. And although I have a very nice graphics card in the 7800 series, my rig still has an AGP slot instead of PCIe ...
But I've invested a lot of time and effort (and some money) to tune my system and that pays off 8-)
If you're willing to invest time and effort in boosting your experience too, then read
this tread and
this one. It worked miracles for me! And if you have a dual core machine
this is also very good reading material

But of course, if you want the icing on the cake, go and talk to Michael Greenblatt of
Flight Simulator Graphic Solutions. It is such an eyeopener ... and if you'd ask me that