Confused over FS9 performance

[reverse_thrust]

Hi everyone.
Last year I got a new PC.
AMD64 3200+, 1.5GB RAM, Asus AS8-X MOBO, GeForce 6200TC PCI-Express, 250GB HDD, 19" LCD monitor, DVDRW, 400W PSU.
Now this PC was kind of a gift, so I had to work to a tight budget.
My system is well tweaked (no useless services etc). I also think I have a good fs9.cfg setup.
Anyway, I decided to get FS2004 and for the most part it performs fairly well with alot of the sliders to the right.
I have FS Global SE and Traffic 2005.
If I use the 'fair weather' theme I can get good framerates and a smooth feel even at busy airports, although alot of AI traffic can start to alow things down.
However, once I use real-weather (I like FSMetar for this) I can see framerate drop in to single digits. This happens regardless of AI traffic, autogen, etc.
Now I'm wondering why this is. I'd have though my CPU is well capable and my memory is OK too. So is it my GPU that's the problem? I know a 6200TC is a bit ancient but I don't know what I could replace it with as many new cards need a higher rated PSU than I have.
I am considering one of these two cards
a 7600GT w/256 DDR3
http://www.ebuyer.com/UK/product/106578/rb/28456182067
or a 7900GS w/256 DDR3
http://www.ebuyer.com/UK/product/125936
Now both of these cards are, for me, expensive.
I've seen reviews of very similar cards, but they tend to concentrate on benchmarking Doom3, Far Cry, etc rather than a flight sim.
So, in your opinion, would either of these cards make a *significant* improvement to FS2004's performance in cloudy weather? By significant I mean framerates of at least low-to-mid teens.
All comments gratefully recieved.

Matt

[DizZa]

As long as the 7900GS fits into your computer and can run on your power supply, GO FOR IT! The 7900GS is a really nice card! The 7600... is not very goood.

[JSpahn]

Seems you have your OS under control. 1.5ghz memory seems like a memory mismatch what do you have 1gig and a 512 stick? or 3 512's?

Kinda a shot in the dark knock it down to 1gig and test.

Have you upgraded your FS to 9.1? I dont know if this will help but it should be done.

Your video card should run fs fine Im running a 6800 on AGP and I get decent performance with my settings to high. Also Nick N has a set of windows tweakes you might want to try out. Im not 100% sure where this info is on th forum but it helped me out a bunch.

[Mees]

An X1900/50 would also be a nice option. AFAIK the X1900 has more pixel shaders and the image quality is even a bit better than from the 7900. Dunno about the prices though...

[reverse_thrust]

I'm using 9.1.

I've got a 1GB and a 512MB stick, both PC3200.
I've just taken the case off and had a look at the PSU.
It's +12V 17A, so that put's the 7900GS out of reach as it needs 20A.
Most 7600GT's seem to want 18A, and my system is a budget one.
So I don't think I'll want to risk any damage by overloading it.

Also, you may not know, but a 6200TC has 128 on board and takes 128 from the system.

Masternerd, what do you mean by "knock it down to 1gig and test"?
Do you mean that I should disable the 512 and check FPS again?

Matt

[JSpahn]

Just a shot in the dark but some motherboards accept matched memory better and there may be performance issues if using different size memory.

[reverse_thrust]

An X1900/50 would also be a nice option. AFAIK the X1900 has more pixel shaders and the image quality is even a bit better than from the 7900. Dunno about the prices though...

Thanks for suggesting those cards.
Prices are comparable to nvidia, but both need 30A on 12V  :(

[dcunning30]

I maybe smoking crack, but I'm not sure this is a graphics card problem.  I think having lots of AI traffic is more taxing on the CPU than the GPU.

[ctjoyce]

The RAM is fine. Don't play with it, don't touch it, just leave it. Its only when sticks very in speed that it slows everything down, but not when size differs.

Your problems lie with your CPU / GPU choice. Both are a little below par for a flight sim. The 7900GS is a good card and I stand by it, but the X1950Pro is quite a bit better. Going with what seems to be true, ATi for single card setups, nVidia for dual.

Also what PSU do you have. Droping in a Thermaltake 600W toughpower, even a Hiper Tpye R will help loads, as you have enough power for everything in the system, and ontop of that you can overclock your processor which again will help tremendously.

Cheers
Cameron.

[JBaymore]

Masternerd, what do you mean by "knock it down to 1gig and test"?
Do you mean that I should disable the 512 and check FPS again?

Matt,

Many motherboards are set up so that they run the RAM in Dual Data Rate mode only when there are certain configurations in the (usualy) four RAM slots.

[reverse_thrust]

Well thank you all very much for your comments.
After further research I have concluded that I would need a new PSU. Unfotunately that would raise the cost too much.
I did do a fresh reinstall of FS9 with no addons. I took off from KSEA.
With 'fair weather' I can run a smooth 20FPS (according to the sim - I'm not an FPS obsessive) with everything maxed out. Pretty nice I thought.
Then I downloaded real weather and the FPS went to 2.5  :o
So, it's clearly all those lovely fluffy clouds that are causing the damage.

I did get a copy of FS2002 Pro (going cheap these days) and tried the same thing.
I lost some FPS (to be expected, as the clouds aren't as detailed) but it was, generally, a smoother flight.
One interesting thing I noticed was less 'shimmering' in FS2002.

So, I think I have an acceptable compromise here.
I can use FS9 for fair weather flying (aka sightseeing) and FS8 for IFR flights.
Any potential upgrades shall be put on hold - most likely until FS11!
Thanks again for your help.

Matt

[JSpahn]

Masternerd, what do you mean by "knock it down to 1gig and test"?
Do you mean that I should disable the 512 and check FPS again?

Matt,

Many motherboards are set up so that they run the RAM in Dual Data Rate mode only when there are certain configurations in the (usualy) four RAM slots.  Usually, the slots are looked at as two "pairs", and they have to either EACH have a single matched chip in them, or the first pair has to have two matched chips in it, or the four slots have to all have matched chips in them.

Otherwise, the RAM runs in single channel mode........ thereby slowing things down.  

So you MIGHT be faster with a gig running DDR rather than one and a half gigs at SDR.  Sort of counterintuitive... but possible.  Read your mobo manual.

best,

..................john

Well put John! Thank for the clarification

[congo]

Your 6200 is the sucky bit in your PC.

Grab a 7900GS and try it, if the PSU can''t handle it grab a cheap 500w+ generic cheap to tide you over.

I'm running a highly overclocked A64 rig with NF4-SLI chipset 2gb ram , 7900GS, 3 x SATA2 HDD's, DVDRW, etc all on a cheap 470w PSU, not recommended, but hey, it's working and has worked for around 2 years now.

Get your ram into dual channel mode and measure the difference in performance, you may be surprised that you'll get better performance from less ram that is properly configured.