I've posted this here rather than in the Hardware Forum because I felt it might be of general interest.I have a Dell Dimension 2350 with 2MHz processor, 512MG memory, 60GB 7200rpm disk, and Intel Extreme Graphics built into the mother board, with a 19" Nokia 445Xav monitor running under XP Home Edition with SP2 and FS9.1, and Norton AntiVirus 2003.Extreme Graphics isn't extreme and I'm thinking of getting a separate video card. Before doing so, I decided to try to run some tests using System Monitor. (Start/Run then type "perfmon.msc" without the quotes.) The two values I monitored were %Processor Time and %Disk Time for the physical disk.I set up a flight using the stock Cessna 172 with UK VFR Photographic Scenery and VFK Terrain (19m grid) at 2500ft QNH and 100kt IAS. Weather was scatterd clouds, 20 mile visibility, with no precipitation. I had no AI aircraft.I'd changed fs9.cgf using the utility that came with VFR Photgraphic Scenery. I normally get 16-18 fps under these conditions with a few excursions outside this range. I ran 6 cases as shown below where:- Visible means running FS9 full screen at Alt-Tabbing to switch to System Monitor- Invisible means running FS9 in the background (Settings/General/Pause otask switch unchecked) showing System Monitor all the time- Unlimited means the display is set to unlimited fps- Limited is with fps limited to 15 fps- No NAV means Norton Anti-virus 2003 disabled.I collected 6 samples for each case, each sample about 2 min in lengthThe average results are: %Processor Time %Disk Time1 Visible Unlimited 99.0 8.72 Invisible Unlimited 12.5 23.03 Visible Limited to 15fps 98.9 15.34 Invisible Limited to 15fps 12.4 14.25 Visible Unlimited No NAV 98.7 7.26 Invisible Unlimited No NAV 7.7 10.9I compared a number of cases while attempting to determine if the differences were statistically significant using Student's-t distribution with the following results: Processor Disk1 & 2 S S1 & 3 S P2 & 4 N N1 & 5 S N2 & S Swhere- S implies statistically significant- P implies possibly statistically significant- N implies not statistically significantTentative conclusions are:- comparing cases 1 & 2, it appears that only about 12% of the processing time is needed to "fly" the simulation with about 88% needed to drive the video. % Disk Time may be constrained by the processing load in case 1- comparing cases 1 & 3, limiting fps reduces the %Processor Time and possibly increases % Disk Time - comparing cases 2 & 4, limiting fps doesn't affect %Processor Time or %Disk Time when the video isn't being driven- comparing cases 1 & 5, disabling NAV while driving the video reduces the %Processor Time but not doesn't significantly affect %Disk Time- comparing cases 2 & 6, disabling NAV while not driving the video redfuces both the %Processor Time and the %Disk Time.I suppose I should add a "health warning" because, it appears that whenever someone proposes changed settings to improve performance someone else will say it worsens or doesn't affect performance so these results might not be reproducible. Also statistically significant doesn't mean much unless the underlying physical mechanism can be explained. I'm not sure I know enough about FS9 to do that but hope other may contribute. For example, what do changes in %Disk Time actually mean for FS9?

Posting the previous message messed up two tables in it, even though I used spaces not tabs to space them out!!!After "I collected 6 samples for each case, each sample about 2 min in length" there should be a table with two columns of numbers; the 1st column headed %Processor Time and the 2nd %Disk Time.After "Student's-t distribution with the following results:"there should be a table with two columns of numbers; the 1st column headed Processor and the 2nd Disk.I hope this isn't too confusing.

In regards to the video card for your Dell, I believe that you can add only a PCI bus card in that machine. Only the built in card has an AGP bus. The only card I could fine for my Dell 2400 Dimension was the PNY Technologies VERTO with a G-Force FX 5200 PCI. www.pny.com Bit of a problem to get on board Extreme Graphics card turned off, but it can be done and there is information on the Dell Web Site about it in the Video Card Forum. It made a bit of a difference, but nothing like double frame rates or anything , due to the PCI bus. Next PC I get will have separate Video card and PCI Express.

Thanks. That's more or less what I understand. I believe it may be necessary to change the BIOS to disable the on-board video?

That is all fine but I am not sure all these numbers tell us anything interesting or of practical use for a simmer. Unless I am missing something.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

I'm hoping to increase understanding of what limits FS9 performance which seems to be a regular problem here