TS2012 frame rate performance charts

[snowstorm]

Here's one chart that illustrates the frame rate issue I'm seeing in TS2013. It shows frametimes from the NEC Early Clocker scenario. Lower is better in this chart - for reference, 20ms frametimes are equivalent to 50 FPS, 30ms indicates around 33 FPS, and so on.



It looks as though the game is running at two speeds at once. The frametime log shows what's actually happening - here's a sample of ten consecutive frames:

24.568
17.048
24.522
17.477
24.32
17.725
24.393
17.273
24.463
17.242

It's bouncing between two significantly different frame rates, delivering one frame in 24ms, the next in 17ms, then 24ms, then 17ms, and so on. This seems to indicate why, despite frame rate gains on my system of 50-100% after the TS2013 upgrade, it either feels more stuttery than TS2012 or doesn't feel as smooth as would be expected from the large frame rate increases.

I wondered if TS2012 was just as bad or whether another game would be. To get some idea about that, I settled on a "frametime deviation" measure that indicates the severity of this issue based on how much the frametimes deviate from the mean on a frame-to-frame basis (e.g. frametimes of 20-10-20-10-20-10 would correspond to a frametime deviation of 33%). Here are my results:

Code: Select all

                                                          FRAMES PER SECOND
                                                TS2013          TS2012          Change

Horseshoe Curve 'The Champion'                  72              45              60%

Northeast Corridor 'Early Clocker'              59              30              97%

Oxford-Paddington 'Rush Hour Run'               72              46              57%

West Coast Main Line 'Royal Scot'               53              33              61%

London-Brighton 'Seaside Express'               41              21              95%

Oxford-Paddington 'Rush Hour Run'               30              30              0%
(FXAA 4xAF FPSLimit=30)

London-Brighton 'Seaside Express'               30              20              50%
(FXAA 4xAF FPSLimit=30)

Battlefield 3 'Gulf of Oman'                    47              n/a             n/a
(High quality, 64 players)

                                               FRAMETIME DEVIATION >15%
                                                TS2013          TS2012

Horseshoe Curve 'The Champion'                  15%             4%

Northeast Corridor 'Early Clocker'              91%             17%

Oxford-Paddington 'Rush Hour Run'               31%             6%

West Coast Main Line 'Royal Scot'               54%             21%

London-Brighton 'Seaside Express'               18%             1%

Oxford-Paddington 'Rush Hour Run'               8%              7%
(FPSLimit=30)

London-Brighton 'Seaside Express'               5%              1%
(FPSLimit=30)

Battlefield 3 'Gulf of Oman'                    4%              n/a
(High quality, 64 players)

                                               FRAMETIME DEVIATION >30%
                                                TS2013          TS2012

Horseshoe Curve 'The Champion'                  5%              0%

Northeast Corridor 'Early Clocker'              46%             1%

Oxford-Paddington 'Rush Hour Run'               12%             0%

West Coast Main Line 'Royal Scot'               21%             2%

London-Brighton 'Seaside Express'               2%              0%

Oxford-Paddington 'Rush Hour Run'               1%              0%
(FPSLimit=30)

London-Brighton 'Seaside Express'               0%              0%
(FPSLimit=30)

Battlefield 3 'Gulf of Oman'                    1%              n/a
(High quality, 64 players)

In a nutshell, TS2013 is pumping out far more frames, but on my system, it's doing so with much less consistency than TS2012. FPSLimit reduces the problem to a large extent.

[GaryG]

Hi

A possibile cause for the two rates you're seeing. Running a recent Intel CPU? Perhaps it is running in variable speed mode depending on the actual CPU load. This could be impacting the actual video output.

I have seen some video rendering speeds (and CPU clock rates) vary while the rendering was occuring. I assume the CPU wasn't quite busy enough to keep it at the high clock rate, perhaps due to "pauses" while doing disc read/writes.

I think the CPU can be locked at the high clock speed with a BIOS setting but I haven't looked too hard because I run my computer 7/24 and I don't need the extra hydro useage and cost as well as the added heat.

GaryG

[up_8677]

I doubt that. Intel SpeedStep is pretty smart, and if the CPU is under even modest load it won't throttle back the clock. Even if it does, it responds instantly to load.