TorstenD (2016) wrote:I just recently got a new laptop with an i7/8GB and a gtx960/4GB.
It is able to run flightgear at 1920x1080 at 30-40fps when flying around
KSFO with the c172p, ALS, all shaders max
A 960 was about my conclusion too [1] for very conservative requirements to run @1080p with settings turned up really high (but not everything like trees maxed). I was being conservative: I expect something closer to 40-60+ FPS with todays more performance intensive C172P and effects with trees turned up but not maxed, but this for an estimated i5 desktop CPU (around Sandybridge/2012). Torsten's 2016 CPU may be slower as it is a laptop, while being a newer technology than an i5 Sandy-bridge.
From that thread, legoboyvdlp uses a GTX 920M (laptop) and can run ALS at max shaders. From his screenshots he has trees, maybe cloud density, and lods settings turned lower, and his laptop's resolution is smaller than 1080p. It goes to show how optimised ALS is on the GPU side.
Website with GPUs sorted by approx. benchmarks: link.
A 920M is 300, and a 960 is ~2300 in the current ranking. A GTX 660 from around ~2012 as Icecold mentions is ~1300, exactly in the middle of that range.
Very high FG settings and control panel (driver) settings can use up GPU time though. Trees at ultra (maybe memory related) and overlays (definitely GPU) can suck up performance. Having transparency aliasing at supersampling can then make both of those even slower. GPU drivers these days have supersampling AA (NVIDIA DSR) to give the GPU something to bottleneck itself on - AIUI presumably because games are designed for current low performance consoles that are popular, so they don't have fundamental uses for lots of GPU power, and games drive GPU sales/development a fair amount.
Mathias (2012) wrote:Our integration of the particle systems
need to be rethought as this contains geometry with culling disabled which
makes a pagedlod just never expire. Switching the particle systems off works
pretty good so far.
Wondering if this is still the case..I recall wkitty42 having the impression [2] that volcanoes/waterfalls could consume processing power even when being out of range - maybe it was just that they didn't expire after visiting them to test(?).
Mathias (2012) wrote:OpenGL wise we are basically geometry setup bound - at least for the
models.
..
That still means that for setting up that one draw with 3 triangles is about
as heavy as setting up say 500 triangles
..
Appart from OpenGL we spend a lot of time in scenegraph traversal.
Interesting. I found out recently that I get 2x+ the FPS, while not being GPU fragment bound, looking at a piece of ground close up or empty sky so one effect fills the screen, compared to looking at a scene in the horizon at ENBR. I made sure I wasn't fragment bound by shrinking window size right down, so it's unlikely to be overdraw of trees etc. Not sure if I was vertex bound, but probably not. This occured even with trees off, OSMCity off, and all LoD ranges set to <= 3.7km reducing vertices. It still occured with shaders turned down to minimum. AI traffic was off. I was using ufo/video assistant so results were not aircraft specific. Increasing LoD:bare from 3.7km to 30km while loking at the horizon in the same direction reduced FPS a lot. This was on a somewhat modern 4-5 year old k-series i5 (stock clocks). This could be scenegraph traversal related with OSG taking a shortcut when looking at ground or sky - not sure how OSG & use by FG has changed over the years.
(As a quick bandaid, perhaps(?) there's a non-rendering part of FG that could be moved to a separate thread on systems with enough cores to free up CPU time, without doing complicated rendering changes.)
Kind regards