S0L said:
Due to the way the old engine worked, it would create and compile each new shader effect as it encountered this and then cache it for future use. This was better for the art team, as they could go wild with all manner of funky shaders, but it did mean that we couldn't pre-cache shaders for everything on every hardware configuration.
What *should* happen (providing the drivers are sensible) is it will cache the compiled shaders up. It might need to do this again for split-screen since the level assets were different there. Basically a run through each track should eventually build up a sensible cache and the problem should go away. It did work back with the drivers that were out back then - can't promise they've not changed things as PC hardware and drivers change all the time. It's a real headache...
Now... The new engine works differently. We have a stock set of shaders that artist can use, but they're all pre-compiled. So we get a huge performance gain - and hopefully much better cross hardware compatibility. The shaders are still configurable by the artists and are created on demand, so we're not sacrificing visuals. If anything, it works better for the art team this way around as they don't need to be quite so technical.
You live and learn is the short answer here...!
I've been making some testing, these are the results I've gotten:
- Phenom II X4 955, Radeon HD6850, June 2012 Beta drivers (Catalyst 12.6 Beta):
Stage "Icicle Valley" in time trial, there's sudden framerate drops in certain locations, like the cave shortcut near the beginning, when entering the second cave close to the end, and a few other places. The framerate drops happen mostly in the first lap and get alot less frequent in the following laps, but exiting to the menu and entering the stage again (with the same character), the framerate drops are back to how they were at first.
- Pentium Dual-Core E5200, Radeon HD4850, January 2012 drivers (Catalyst 12.1):
Same situation as the Phenom II X4/Radeon HD6850 PC.
- Pentium Dual-Core E5200, Radeon HD4850, March 2010 drivers (drivers released in the month after the game was released, Catalyst 10.3):
With these the framerate drops happen in the same locations, when exiting to the menu and entering the stage again, the framerate drops are back to how they were at first as well, but the framerate drops are alot less sudden with these older drivers.
After this I started trying a bunch of different drivers, until I found the first driver where the framerate drops became more sudden, which is the March 2011 Catalyst 11.3 driver.
I tried a few drivers before this one, like February 2011 (11.2), January 2011 (11.1), December 2010 (10.12), they all worked like the March 2010 (10.3) drivers, there were framerate drops, but they were not as sudden as the newer drivers.
I also tried a few drivers after the March 2011 (11.3) driver, like June 2011 (11.6) and December 2011 (11.12), these all have the sudden framerate drops like the March 2011 (11.3) and the January/June 2012 drivers (12.1 and 12.6).
I guess I'll try sending feedback about this to AMD's driver feedback page, but I doubt they'll do anything about this...
Oh well, can't wait for All Stars Racing Transformed.