New gaming rig - performance analysis.

[lydianduck]

Hey; I haven't posted in a while, got this new PC (i5 2500k @ 4.5ghz, GTX580, 8gb Corsair Dominator 1600mhz), right now playing with enb and mods at superb framerate on Patch #4, however I noticed some weird performance bugs. (be prepared to read a lot).

 

 

 

Let me first start off by saying my hardware knowledge is pretty limited, and my english is not perfect either, so some of the conclusions I came to will be completely wrong, I am, however, pretty certain about the observations I made when analyzing this game's performance, so here we go:

 

 

 

When running the game with vsync enabled, I noticed, when I monitor my frames with fraps, that they go above 60 (right now im playing it at 1280x1024 60hz / my old monitor is broken right now.) so correct me if im wrong but this is NOT supposed to happen if my refreshrate is 60.

 

It gets even weirder, this only happens in specific parts of the map. And even more weird, when it happens, a second later the game stutters. This is with vsync enabled, if I disable it, those same areas of the map suffer from insane tearing.

 

So check this out, I remember when I first got the game last year I sent an email to Rockstar about the performance issues I had with my old pc and they told me it was a leak in the memory buffer (mind you, this is NOT supposed to be the video memory management issue that is usually corrected by applying the memrestrict command).

 

So it seems like some parts of the map (very specific parts of the map) are actually running at a slightly higher framerate; This generates a lag when vsync is enabled because different parts are not being rendered in sync.

 

It's almost like when the game is rendering, it has one or two extra frames that doesn't know what to do with them. (im starting to think this is what Rockstar really meant by leak in the memory buffer.

 

One way to alleviate this is by limiting your fps to like 35-40 (with the -refreshrate commandline and contrary to what the readme file says, it's not necessary to use "-framelimit 1", but you have to have v sync enabled either way).

 

 

 

 

Another thing, when I activate vsync and use the refreshrate commandline (with or without framelimit 1) it always caps the framerate a little higher than what I specified, approximately 3 more frames, so I tried capping it at 57, but sometimes it still goes over 60 and I have the same strange stutter/lag.

 

So I decided to go lower, but sometimes it still surpasses the cap I set, so it seems like every time it exceeds the framerate cap (whether it's vsync) or manually set with commandlines the game lags and it's always in the same parts of the map. Btw, lag was present in those same areas with my previous computer as well (x4 955, 6850, 4gb ram).

 

So in conclusion, I wish there was a way to hard limit your fps without exceeding it to avoid the memory buffer issue, I know that forcing it through the nvidia control panel prevents it a little (meaning that it's a little more precise - therefore less lag/stuttering) but it's not exact.

 

 

 

 

Also: Remember the 'eternal loading times with vsync enabled' bug present in older patches, I noticed that if I enable vsync and use "-refreshrate 60" (with or without -framelimit 1) the loading times are still endless, however, if I keep going lower till I hit "-refreshrate 57" the loading times are fast again.

 

So, to somebody who is not very hardware knowledgeable like me, it seems like the game has problems managing those extra frames. Just pointing it out cause im bored, I love computers and I love this game.

 

 

-edit- One last thing, if you check your cpu usage on a quadcore when exploding zillions of cars and making your cpu sweat a little, you'll notice (for example in the task manager) that the first core hits a roof, yet the second is barely being used, this is corrected by DISABLING the first core (it has to be the FIRST one) and suddenly the mouse will feel more floaty in game and you'll have the sensation that more gpu power is being used and the framerates will feel much more stable.

 

 

Thanks for reading!

Edited March 14, 2012 by Brainsick