Is it such a problem that I have a Radeon X600 card?
The short answer is basically yes, that card will not run FSX well at all. Add to that Pc3200 RAM (The 400Mhz stuff you have), and a single core processor (Pentium 4), and you might as well not run FSX. I know it sounds harsh, but that is the truth.
If you want to achieve decent framerates in FSX, you're going to have to upgrade your system, completely (e.g. dual core processor, PC6400 RAM, new graphics card).
On your system I would stick to FS2004. You should be able to run it almost or completely "maxed out", and it will look nice, trust me ;) (FS9>FSX

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Regards,
Celtman - An avid FS2004 user (Since my FSX went balls up and is no longer playable

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