Interesting GPU/CPU Usage

EZ1 · #1 09-11-2011, 04:16 PM

I was just running the London free flight to watch my GPU and CPU usage to see how lots of buildings affect them. I dropped down to around 2000 feet and started following the river from the Tower Bridge Eastward to the sea. While over central London the GPU usage fluctuated between 70% and 80% which I thought was pretty low considering the buildings. I have “Unlimited Building” configured. The CPU usage was distributed fairly evenly over 4 cores running around 50% to 60% on each. The CPU usage stayed consistent for the rest of my flight. However, as I left London and got into the country side the GPU usage maxed out and stayed there until I quit the mission. That is exactly opposite of what I expected. Also, as I posted before, when the GPU maxes out I start seeing usage on the second GPU (not running SLI).

As for I/O I was just watching the HD access light which only blinked once or twice a second throughout the flight. If there was a lot of I/O going on it was happening mostly in the RAID cache.

Anyone have an explanation?

albx · #2 09-11-2011, 04:21 PM

Quote:

Originally Posted by EZ1

I was just running the London free flight to watch my GPU and CPU usage to see how lots of buildings affect them. I dropped down to around 2000 feet and started following the river from the Tower Bridge Eastward to the sea. While over central London the GPU usage fluctuated between 70% and 80% which I thought was pretty low considering the buildings. I have “Unlimited Building” configured. The CPU usage was distributed fairly evenly over 4 cores running around 50% to 60% on each. The CPU usage stayed consistent for the rest of my flight. However, as I left London and got into the country side the GPU usage maxed out and stayed there until I quit the mission. That is exactly opposite of what I expected. Also, as I posted before, when the GPU maxes out I start seeing usage on the second GPU (not running SLI).

As for I/O I was just watching the HD access light which only blinked once or twice a second throughout the flight. If there was a lot of I/O going on it was happening mostly in the RAID cache.

Anyone have an explanation?

alot of bugs?

senseispcc · #3 09-11-2011, 05:15 PM

Try to go under 200 ft. over London and there the fps get a big hit. Especially over the Tower, the Parliament and Buckingham Palace... But in a real fight it never happened.

kestrel79 · #4 09-11-2011, 05:15 PM

Does that 1C splash screen bug still happen where it makes GPU's run really slow clock speed?

I'm running the official version of the game (no beta patch) with an ATi 5850 should I get rid of this screen? Or is this an old issue?

EZ1 · #5 09-11-2011, 05:28 PM

I've done the low flight thing many times, but I wanted to see how the CPU and GPU usage looked over varying landscapes. What I am seeing looks like the GPU is begin under utilized in some cases for some reason. In other situations like in a typical combat mission over the channel, the GPU stays maxed out as I would expect.

NedLynch · #6 09-11-2011, 06:03 PM

I've had the same experience regarding gpu usage, however my gpu usage as measured with afterburner has gone up significantly (from 60-80% to 80-99%) after the beta patch, which I do see as an improvement.

DrSanchez · #7 09-11-2011, 09:19 PM

most probably the cities take a lot of cpu power as well as gpu power. Think about all those LOD swaps and all the data that has to be sent to gpu. gpu is not showing 100% usage because it was waiting for the cpu. therefore in that situation the cpu is the bottle neck.

In the countryside there's not a lot of the cpu to do so the gpu is able to run at full tilt.

EZ1 · #8 09-11-2011, 09:36 PM

But the CPU usage stays relatively low and does not fluctuate regardless of the GPU usage.

335th_GRAthos · #9 09-12-2011, 07:52 AM

You also need to look at the utilisation of the VRAM. The moment your VRAM is full, the GPU will start swapping in order to accomodate for the new graphics. This is when your GPU utilisation goes down (and your fps too) because the bottleneck becomes bringing the data in for the GPU to process them.

Test also flying over the same area above London a second time. You will see a much smoother fly-by the second time (provided the data is still in the memory of you GPU).

Over the sea you do not have any objects to load. Both GPUs (if SLI) work 90%
Over an "empty" (not a lot of objects) map neither. Both GPUs (if SLI) work 70-90%
Over the same map full of objects in order to max the available VRAM of your card, you see the problem. Both GPUs (if SLI) work 50-70%

Look at http://forum.1cpublishing.eu/showthread.php?t=23199

Quote:

As for I/O I was just watching the HD access light which only blinked once or twice a second throughout the flight.

Once or twice per second HDD access is a lot (for me) and shows the amount of data that needs to be loaded.
For me this was solved and I got smoother gameplay by creating a RAMDISK and loading everything there. The new RAMDISK solutions posted in the forum are much more advanced than the ones I knew in the past and made the difference.

~S~