Recently my GeForce 8800 GTX kicked the bucket – the fan had gotten clogged up with bunny fur (from two years of sitting about three feet from the hutch), and running Modern Warfare 2 finally pushed it over the edge – it overheated and fried itself. Although I was borrowing an old ATI XTX1950 that was running fine, I decided this was a sign for an upgrade.
I had read good things about the GTX285 card, which is one step below the leading edge, so I decided to give it a go. I chose the BFG model with 2GB of texture RAM – I know FSX uses a lot of texture ram (all those scenery textures, spec maps, etc all at 1024×1024 in 23 bit have to go somewhere…). The price tag was about $400 – wow, expensive, but OK. Then the gotcha – my power supply wouldn’t drive it (it’s a 450W model), so I had to upgrade that too. Add another $100 (but actually that was a good deal, because it is a Corsair 750W model, which normally goes for $180). I was a little anxious because I had read reports of people going from the 8800 to the 285 and reporting no change in FSX frame rate, but after working in a graphics lab for six years, I knew that couldn’t be true. Or could it?
Today I installed it all and tried it. I decided to be adventurous and up the scenery levels to max (just the autogen levels and scenery objects – I kept all my other settings the same). I learned a number of interesting things about FSX, graphics cards and performance….
- For most scenarios, the 285 improved my performance between 50% and 100%. So overall, this is good.
- Under Win7, there is no difference really in running DX9 or DX10 (same as the 8800), except that in DX9 mode you have better compatibility in terms of features.
- There is a very big difference in performance between native FSX models and FS9 models. For instance, using the default 737 at Tokyo Haneda, I was getting 20FPS. But switch to the Overland 777 (which seems to have a similar number of polygons), and the FPS drops to about 13. With the Opensky 777 (which probably has more polygons), the rate drops to 10. FSX models will give you far better performance.
- The frame rate limiter is very maligned. If you read blog posts a lot of people tell you to turn the frame rate limiter off, as it reduces performance. The truth is a little more complex. Let’s say you limit to 25FPS, and you are flying at 25FPS. If you turn off the limiter, the rate jumps to some higher number (obviously) – let’s say 40. Then turn it back on – you would expect the number to go back to 25 right? Not so simple – it drops to less than that (e.g. 13), and stays there – but only for a minute or two – then it settles at 25. I guess during the first few minutes the engine is calculating some budgets which eat into FPS. So if you are experimenting, give things a moment to settle. This begs the question – why turn it on at all? Simple – you need to divide up your machine between drawing the scene, calculating the simulation, doing the AI and generating the scenery tiles. By limiting the FPS, you cap the amount of resources used to draw the scene, and open them up to the other tasks. You will notice that with the limiter off, the “blurries” on scenery tiles take a lot longer to disappear – this is because you have not reserved any resources for generating the scenery tiles.
In general, the GTX285 is a very nice card for FSX (and it can run Modern Warfare 2 without burning out, so that is a bonus too). I suspect the GTX280 would perform similarly, as the specs are quite similar. Oh and as freebies I got a BFG t-shirt (in my size, what luck), and a copy (via Steam) of Batman: Arkham Asylum. Not such a bad deal.