Strange increase in performance

[DeTeEff]

Good evening

 

I've got no idea on how to put this, but as mentioned in other threads, the performance may suffer when mapping, dmapping, playing, mapping, dmapping, playing, for a while. This time, the mission actually has come to a point where the performance has increased from 35-45 to about 55-60 FPS on the most performance heavy places In other words, there is no area in my mission that eats the FPS...

This without even changing a thing in these places. How is this possible? I've even got DarkRadiant, Spotify, Mozilla with lots of tabs running in the background. It happened some time yesterday also, and then I tried to restart Doom. (I thought that TDM shouldn't be running THAT good ) and then it reverted to its normal FPS for my mission, that for me is around 55-65 and about 30-40 on the most expensive parts...

 

I've got no idea on how to objectively check this change, but I mostly write it down as a documentational thing if anyone else should experience it.

Edited June 5, 2011 by Fieldmedic

[Bikerdude]

For me its down to memory fragmentation in windows, so until today what I have been doing is shutting down doom between each dmap. If I left doom running between dmaps my fps would steadily drop off, but since running memory cleaner (it flushes the ram reducing fragmentation)the fps stays good for longer.

[DeTeEff]

I used to restart Doom too for each change and DMAP, but the first DMAP/map start is more time consuming than the rest so I use windowed mode and keeps the same session running.

[Bikerdude]

well i would look at a memory flushing prog like the one I found then.

[nbohr1more]

LOL.

 

Yes, I've had strange bursts of good performance.

 

I usually chalk-it-up to the Branch Predictor in my Pentium 4 having a lucky streak. Memory fragmentation is certainly a possibility but I am wary of an 3rd party program that claims to help that as it is something more in the domain of motherboard chipset drivers...

 

Oddly, some have reported that having background jobs running is sometimes beneficial rather than a detriment. I can only guess that if background jobs help that the video or chipset drivers were only tested with Heavy Multi-Taskers

[Fidcal]

I saw exactly the same at some stage last year. FPS got worryingly low and I was trying different things to tweak it. Then I had a session where fps everywhere improved. Even the worst place was OK. I never really found an explanation except maybe sessions normally I do a lot of dmapping and some kind of memory leak built up to slow it down. Then in a fresh session everything was OK again. But my confidence in the explanation is fuzzy.

[jdude]

Same thing happened to me a really long time ago. I think I must of turned off background processes and forgot I did it. Or I played a map without dmaping first (I think dmaping slows gameplay performance).

[MoroseTroll]

Hmm... What a nice boost, nbohr1more, from 35..45 to 55..60 fps ! Apparently, an elimination of the memory fragmentation could be much more useful then all my work with idSIMD, seriously. AFAIK, there are at least two methods exist to cope this issue:

 

1. The Low-fragmentation heap feature in Windows. Apparently, Doom 3 doesn't use it because I've found no entries of the HeapSetInformation function.
2. The Page Size Extension (PSE) of Pentium 1 and later CPUs. But Microsoft has implemented this feature (VirtualAlloc with MEM_LARGE_PAGES flag) starting with Windows 2003 Server (I suppose nobody of us is using this OS for TDM) and, ta-da!, Windows Vista.

So, even John Carmack will release the Doom 3 Source, and somebody will implement the PSE support in it, all pre-Vista TDM-gamers won't feel any speed boost. Well, guys, what do you think about?

[grayman]

Same thing happened to me a really long time ago. I think I must of turned off background processes and forgot I did it. Or I played a map without dmaping first (I think dmaping slows gameplay performance).

 

Yes, dmapping first slows performance because dmap, when finished, doesn't release all the memory it requested to do its job.

[Serpentine]

It seems that Doom3 tries to give you a 'smooth' fps, a multiple of 5 and the usual areas are around 15/25/30/35/45/60. Some of the gaps I notice are pretty large, but if I increase my clocks just enough it will flip and give an extra 5-10 fps. Watching the numbers while dmapping or playing with test maps which arnt optimized at all shows there is some sort of biasing going on (or maybe it's just me seeing patterns in the noise).

 

Personally, I find TDM especially is completely playable and 'solid' even at 25fps, while in most games, even with vsync 45 feels painfully jerky and annoying. Don't even bother bringing up rubbish about 24/25/30 fps and whatever else.