I really have no idea what is going on with my system! Just did a flight in the CRJ 700 from Ottawa to Boston. In Ottawa my fps was around 50 and all the way until final approach it was good right up until landing when it nose dived to around 10!! When I checked in MSI afterburner I found the GPU usage had plummeted much to my surprise (really would have thought it would be opposite) CPU usage was not maxed out at anytime either. I'm running medium settings across the board on pretty much everything. Really not sure what is going on!!

Spec is

1 TB Seagate (1000 GB) SATA-III HDD 7200 RPM 64MB Cache
EVGA 750W (Modular) PSU - Low Noise
256GB Samsung PM961 M.2 SSD, Read 3100MB/s, Write 1400MB/s - Silent
Corsair 16GB Vengeance LPX 2133MHz (2x8GB) (DDR4) 
Corsair Hydro H45 (Advanced Liquid Cooling) 
NVIDIA GeForce GTX 1070 - 8 GB - (PCI-E) - DVI/DP/HDMI - HD/4K/VR
Intel i7 7700K - (4 x 4.5 GHZ) - Kaby Lake 
Asus PRIME Z270-P (Intel Z270) - 4xUSB 3.0/2xUSB 2.0

 

How are you measuring CPU usage?  The only number that really matters is the load on Core 0 (or the first P3D core if you have an AM set that changes it from core 0).  Total CPU usage is the average across all the active cores, which will rarely be maxxed out out, even when you've actually hit the wall on the main thread on core 0.

I would suspect your CPU got hit hard with AI or airport scenery object workload to drop the framerate in the manner you describe.

7 hours ago, w6kd said:

How are you measuring CPU usage?  The only number that really matters is the load on Core 0 (or the first P3D core if you have an AM set that changes it from core 0).  Total CPU usage is the average across all the active cores, which will rarely be maxxed out out, even when you've actually hit the wall on the main thread on core 0.

I would suspect your CPU got hit hard with AI or airport scenery object workload to drop the framerate in the manner you describe.

I was using process lasso. Interestingly i reloaded the sim later at the same airport and got better fps. The difference? It wasn't snowing. But then it was on the departure and that didn't impact things.

Well, this is really easy: if your GPU is below anything from 95-100% load, you are in a CPU limited situation, no matter what CPU load you see by whatever tool you use. The ONLY exception to this rule is using frame limiters of course...

Besides that, this annoying FPS loss on destination is something that I stumbled across throughout my simming career of ESP based simulators and never totally got rid of it. Now, using P3Dv4.5 and a FPS limit of 30, it almost totally vanished, but from time to time, I still suffer from lower FPS at destination. Never found the actual cause to this "phenomenon"...

3 hours ago, Rob_Ainscough said:

Snowing would increase GPU usage not reduce it ... are you sure your GPU wasn't getting too hot and throttling due to increased load from rendering snow?

Cheers, Rob.

That's possible, I didn't pay much attention to the temp was just looking at the usage!!

My VRAM usage? Never really monitored this, but I did not tweak that much things increasing VRAM usage. I know about your thread regarding VRAM here, might be the case but as the "phenomenon" is only sparsely occuring nowadays, it is rather hard to put a finger on it. If I remember, I will check VRAM usage the next time I observe reduced FPS on destination, sure.