I'm running TS2010_SP2 on the following:
P4 @ 3.4Ghz on Asus P5AD2-E Premium mobo - Over-clocking set to Auto
3Gigs DDR2 @ 533Mhz
500G 7200rpm 32MB buffer HDD on SATA
BFG GeForce 9800 GTX+ 512MB video
Trainz runs well as long as I keep the draw distance at or below 3000m. Lower that when I am in congested areas such as large yards, or cities with lots of buildings.
I have also seen better performance when scenery detail is no higher than Normal. Setting to Low does pretty much the same thing as setting draw distance lower.
I usually have Antialiasing turned off. It really doesn't do much in Trainz anyway.
Make sure that Antialiasing is set to "application controlled' in your video control panel, or Trainz will use the default setting of the driver.
Also, make sure that you have the latest video drivers.
Increasing video memory probably won't buy you much. My problem is not frame rate, but rather a "choppy" performance as the train moves through the terrain. This seems to be due more to CPU and memory system than video.
Increasing system RAM beyond 3GB won't do anything at all, unless you are running a 64 bit CPU and OS. 32 bit can only use about 3GB (for Windows XP, you may need the /3GB switch in the boot.ini file in order to use even 3GB.)
After reading other threads on this issue, I believe that a lot of the problem is how TS2010 was coded (using a lot of old code), rather than hardware issues.
As far as I can tell, despite all of the issues, TS2010 runs better on my system than both TS2006 and TS2009. The difference between 2006 and 2010 is the draw distance.
With TS2009, the draw distance was upgraded to 5000m. This puts a huge strain on older systems.
The solution is to be happy with not more than 3000m distance, and normal detail for everything.
Also, when creating your own routes, try not to over-populate. Too much scenery in one area will slow the performance significantly.
Building large yards (and filling them) will cause huge performance hits.
I should have realized this when I built the 8,000 car Selkirk yard on my CSX River Line route. No way am I ever going to get even 1,000 cars in there and still move any trains.
One more thing: If you buy 2010, make sure you get all the service paks.
I would assume that the download version is up to date, but when you buy the DVD, that will depend on how long your supplier has it sitting on the shelf.
My final vote is to go with TS2010. There are a lot of improvements over 2006, and it will run on your system.
FW
