And having spoken to a man I know who's spent 5-6 years building computers and he says FS9 is much more GPU than CPU dependant, and given my current one, with 1GB but very low clock speeds, versus one with 4.3 GHz clock I think I won't ever upgrade to FSX.
Saying that FS9 is "more GPU than CPU dependant" doesn't automatically mean it will always get a benefit when upgrading the GPU.
It only means FS9 use the CPU even worse than GPU, which is not the same thing. FS9 doesn't use more than 1 core, so you will not see huge benefits upgrading the CPU, considering that any CPU you buy today it's multicore.
But this doesn't mean it will *USE* a better GPU, because it will not, not after a certain point, where you will see benefits only if you were trying to drive a very high res monitor, or several of them. Only in that case a better GPU will help, just because of the raw fill rate.
However, the problem it's a bit more complex than that, and of course someone that builds computers can't possibly know how the *software* you are trying to run works, which in this case happened to be made by US so please, just accept the explanation:
In order to achieve a decent image quality in KLAX for FS9, since the FS9 graphic engine doesn't support a lot of the shaders we used in the FSX version, we had to simulate them using more polygons and, due how FS9 works, they affect both the CPU and the GPU, while if we were in FSX, it would be a purely GPU issue (so you WOULD get a benefit from updating the GPU, in FSX ).
On top of that, since the FS9 graphic engine doesn't support more than 32K polygons per drawcall, we had to get rid of LOD levels in FS9, otherwise the object would simply disappear, because the polygon count with LODs exceeded what FS9 supports. FSX has this limitation much higher so the FSX version, on top of being more GPU dependant, it also enjoys LOD, which help with the frame rate too.
That's why is wrong keep using FS9:
sceneries that have exceeded its capabilities are already out, and this trend is not going to reverse. On top of that, you can't even purchase better hardware to substitute the missing capabilities of the FS9 engine, because everything you will buy today will be heavily multi-threaded, and FS9 doesn't support any of this, and having a powerful GPU that will help running shaders code more fast, wouldn't help much in FS9, because its scenery format doesn't use shaders much.
(Sorry if this isn't your reason - you'll stop making FS9 stuff and then lose me as a customer )
Even if we wouldn't stop, we'll keep pushing the ahead the usage of the FSX capabilities, which means the FS9 version will not just look worse, but it might be even slower, but there's no way we'll do anything to fix this, because it would mean undermining the FSX version, which is the only version we care.
The only reason we offer an FS9 version in the first place, is to allow users to upgrade to FSX without having to say "I have too much money on addons", because it doesn't apply with *our* addons, were the cost to upgrade to FSX is exactly ZERO.