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Slowdowns/Bottlenecks

Last response: in Graphics & Displays
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October 13, 2012 4:55:30 PM

Now that I have fixed my problem (on my own), I will make this a thread where everyone can post problems like this. I will show causes and any fixes if possible. My original problem happened when my CPU heated up, which bottlenecked GPU but fixed by turning off hyperthreading. Virus-caused issues are not posted here.

Causes of Slowdowns/Bottlenecks and Fixes:

Low-end/faulty hardware FIX get new hardware

GPU Heating Up: FIX Dont OC, check cooling, check power supply

CPU Heating Up: FIX Turn off HT, check cooling, dont OC, check power supply

Software Conflicts: FIX figure it out youself

Bad Drivers: FIX Rollback or update drivers

Slow Hard Drive: FIX Check some BIOS settings (sometimes changes itself), defragment, free up space

More about : slowdowns bottlenecks

October 13, 2012 5:08:06 PM

In my experience, some games are really CPU hungry. BF3 keeps my GPU pegged at 95+% usage according to MSI Afterburner for my 7850. On BC2, I get 60-70% usage. I have an overclocked 2500k, too, which surprised me that BC2 didn't use more of my 7850. A better CPU will help with CPU intensive processes.
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October 13, 2012 8:21:26 PM

I meant a fix to prevent the CPU to stop using the GPU if CPU is used too much.
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a b U Graphics card
October 13, 2012 9:12:01 PM

get a better cpu.
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October 13, 2012 10:38:09 PM

rgd1101 said:
get a better cpu.


No need for your comments.
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a b U Graphics card
October 13, 2012 11:42:03 PM

I'm not really sure what you are trying to achieve here... If your CPU is running at 100% and you are only getting say 30 FPS your GPU will only run fast enough to match what your CPU can support... so if your CPU limits your FPS to 30 and your GPU is able to run the game at 100 FPS ( with a faster CPU ) it will only use the resources it needs to maintain 30 FPS leaving the GPU to run at say 30% load... because the CPU will bottleneck it to that frame rate.

So i'm going to have to agree with rgd1101 get a better cpu, OR overclock the one you have right now.
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October 14, 2012 12:15:00 AM

Derza10 said:
I'm not really sure what you are trying to achieve here... If your CPU is running at 100% and you are only getting say 30 FPS your GPU will only run fast enough to match what your CPU can support... so if your CPU limits your FPS to 30 and your GPU is able to run the game at 100 FPS ( with a faster CPU ) it will only use the resources it needs to maintain 30 FPS leaving the GPU to run at say 30% load... because the CPU will bottleneck it to that frame rate.

So i'm going to have to agree with rgd1101 get a better cpu, OR overclock the one you have right now.


You misunderstood,,,, and my CPU is good enough. Generally,, my FPS is 60 for the most part and CPU usage is usually not near maximum. But,,, when CPU usage nears maximum,,,, the CPU stops utilizing the GPU, to allow for more CPU processing. I am looking for a way to prevent that from happening.
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a b U Graphics card
October 14, 2012 3:29:03 AM

coolitic said:
You misunderstood,,,, and my CPU is good enough. Generally,, my FPS is 60 for the most part and CPU usage is usually not near maximum. But,,, when CPU usage nears maximum,,,, the CPU stops utilizing the GPU, to allow for more CPU processing. I am looking for a way to prevent that from happening.



Could you please list your computer specs? and maybe give an example of what games and under what situations you are seeing this happen?
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October 14, 2012 3:38:00 PM

CPU: Sandy Bridge Quad (8 Threads) i7 2630QM up to 2.8 Ghz (no OC)

I/D GPU: Intel HD Graphics 3000/Geforce GTX 560m 1.5 GB (OC But still under maximum stable clock, no voltage changes)

RAM: DDR3 8 GB (4 slots) Dual Channel 1.6 Ghz Total

Motherboard/BIOS: Alienware M17x R3/A08 BIOS

Happens under games like Crysis 2 (with DX11 and High-Res Textures), Starcraft 2, Blacklight, etc.

Generally, I still get full FPS for all games (a little lower at times), but even with full FPS, I have to lower settings to prevent this problem (so I cant really use the full power of my PC). Please do not post comments if they are not constructive (like rgd1101).
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a c 84 U Graphics card
October 14, 2012 5:11:06 PM

what you are seeing is indeed cpu bottlenecking and theres nothing you can do about it that hasn't been said allready. Also the cpu doesnt have to reach full 100% load to bottleneck a game, and since you have 8 threads available such a loading would be highly unlikely in a game anyways. As long as the main thread fully uses one core (or any other thread for that matter) it will create a bottleneck for the whole application and prevent it from running any faster. And as a result the gpu usage will drop since the cpu cant do its stuff fast enough to keep the gpu fully fed with new data. So it doesn't just 'stop utilizing the gpu' as you said, it still is using it as fast as it possibly can.
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October 14, 2012 5:48:20 PM

I don't get this problem, and his 2630QM is almost as good as my 2500k, although it is overclocked. Since when did a 6000 score on PassMark bottleneck a 560m on Crysis? Crysis should be severely bottlenecked by GPU except at low resolutions.

Edit: didn't realize it was Crysis 2. Nevermind.
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a c 84 U Graphics card
October 14, 2012 6:19:44 PM

buckcm said:
I don't get this problem, and his 2630QM is almost as good as my 2500k, although it is overclocked. Since when did a 6000 score on PassMark bottleneck a 560m on Crysis? Crysis should be severely bottlenecked by GPU except at low resolutions.

if by almost you mean like 50% and crysis2!=crysis
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October 14, 2012 9:24:21 PM

buckcm said:
I don't get this problem, and his 2630QM is almost as good as my 2500k, although it is overclocked. Since when did a 6000 score on PassMark bottleneck a 560m on Crysis? Crysis should be severely bottlenecked by GPU except at low resolutions.

Edit: didn't realize it was Crysis 2. Nevermind.


IT IS NOT BOTTLENECK. Generally, the CPU uses 1 thread for GPU (with the exception of Kepler GPU's, which can have as many as needed). Unfortunately in my case, when CPU is being needed so much, it sees that in order to get more CPU processing, it must use that GPU thread as a CPU thread(at least to my understanding).
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a b U Graphics card
October 14, 2012 10:06:37 PM

That's not how it works.. you have a CPU bottleneck.
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October 14, 2012 10:47:59 PM

If it was CPU bottleneck, then the GPU usage drops would not be like spikes (drops to 0 very sharply then sharply gets back up).
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a c 84 U Graphics card
October 15, 2012 10:28:19 AM

coolitic said:
(drops to 0 very sharply then sharply gets back up).

ah new info :lol: 
post an Afterburner screenshot with temps, clocks and load%?

edit also cpu temps would be nice and Windows resource monitor info on disk activity might be usefull as well, maybe it's loading stuff from the hdd like textures and stuff, and laptop hdds aren't known for their speeds...
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a c 177 U Graphics card
October 15, 2012 10:34:49 AM

Just a few penceworth and have n't tried it myself but it is possible to use Task Manager to change the program affinity-effectively forcing it to use fewer cores?
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a b U Graphics card
October 15, 2012 10:56:39 AM

While playing a game without limiting the FPS you would think the GPU should pretty much always run at 100% whether it be GPU or CPU hungry as it is trying to render the maximum frames possible. In regards to your actual question some games actually have the option for things like multi-threading in their settings, LA noire has this setting and it completely destroys the framerate when it is turned on for some reason. Some games do actually run better if you force them to run on 1 core which you can do with task manager, right click on the aplication and click go to process then right click on that and go to set affinity, then just choose how many cores you wish the program to use. I think this problem is likely a CPU bottleneck as well, at certain points while playing a game the CPU is maxing out and then having to catch up with the GPU which in turn is having to stop rendering so it can sync back up with the CPU.
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October 15, 2012 8:42:41 PM

I am limiting FPS, via V-sync and triple buffering (adaptive V-sync somehow disappeared in my mobile drivers)
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!