Why is my (AMD Fx 8350 Stock speed's) Bottlenecking My (Nvidia GTX Evga Acx SC 780)

Hardware Hub GPU
41

I highly doubt it's the GPU. I read through this whole thread and based on all the info thus far, I'd be looking more closely at the motherboard and PSU. 

Falcon saunier, what is your CPU frequency and voltage the moment it spikes to 100% load and frame rate drops? Same with the GPU, what is the frequency and voltage of the GPU during the frame rate drop? If you see the frequency and or voltage drop on both at the same time, then it's most likely a problem with the PSU. If this only happens to the CPU, then it's most likely your motherboard.

If the CPU throttles back (for what ever reason), it will max out (because it can't handle the same amount of work at much slower frequencies) and will drag your GPU down with it. The CPU feeds the GPU data and thus if the CPU jams up, so does the GPU. But if the GPU falls on it's face, the CPU should not be affected and shouldn't experience load spikes. It should just show a performance drop in the game.

*edit* Just wanted to add that if my logic is flawed or I'm wrong, someone feel free to correct me. I'm just sharing my humble opinion based on my level understanding. 

42

I agree with MEC-777. Monitor your CPU / GPU clock+ voltage with CPU-Z and GPU-Z (or Afterburner for the GPU)

43

Thank you for the awesome response, also sorry for taking a while to respond, so i have been doing more testing and yes the voltage is dropping on both the gpu and cpu during the drop's here is a picture to show that. (CPU  http://i.imgur.com/zmtLMs3.png ) (GPU http://imgur.com/a/QWudJ )

44

No prob, just trying to help. :)

So your CPU core speed dropped to just under 1.4GHz and voltage down to .864. On your GPU, only the core speed dropped and only by 200MHz. GPU memory clock did not drop and the voltage only dropped slightly. 

Pretty sure I've seen the same behavior with my 7950 when the game I'm playing hits a point where there is less demand. 

It looks to me like the GPU is throttling back to wait on the CPU which is being choked. So again, I really don't think the GPU is the problem. At this point I'm thinking it's the motherboard.

Is there anyway you can get your hands on a 990 chipset motherboard just to try out? 

45

yup! i had the same kind of problem with another low end Asrock board (880GM-le FX) you have to get a new board.

i would recommend Asus's Sabertooth 990fx gen3/rev2 because of the Pci-e 3.0 support and the longer warranty.

i also used the Crosshair V Formula wich gives you nice overclocking capabilities, decent onboard Audio and the best: Intel Ethernet :D.

these Boards are Expensive but i had the best experiance with those.

46

http://pcpartpicker.com/p/YfZI Im thinking of getting this soon. :D but sadly i cant test with any motherboards with the 990 chipset well at lest until l buy one.