I am currently running FSX with an i7 920 over clocked to 4 GHz. My GPU is a GTX 285. I am looking at replacing the GTX 285 with a GTX 580. I believe at the present that my current GTX 285 is a bottleneck to the i7 920 which accounts for some random graphics spikes, and some occasional painting lags. My FSX is loaded with software, and is maxed out for the best play on a 26 inch monitor. I would rate my current overall performance with FSX as excellent.

The obvious question is what will provide the best improvement (performance and picture quality) for FSX - an upgraded CPU or an upgraded GPU? Better stated, what is the balance between CPU and GPU for best results when running FSX? When does one become a bottleneck to the other?

Will appreciate any and all comments.

Regards,

Flight Ace

Sean Grenyer wrote on Aug 28^th, 2011 at 2:53pm:


Sean,

Thank you for your input.

I was considering upgrading my current configuration with one of the following.

1.      New CPU (i7-980)which would be compatible with my current P6T Deluxe 1366 Motherboard and/or an upgraded GPU.

2.      Upgrading to an i7-2600K. This would require a new motherboard as well as RAM and would be the most costly.

In the meantime I have completed some research into how well the performance of the i7-980 and a GTX 480 compare to my current configuration. What I found is that in some cases it was the same, and in other cases a bit better up to 4.5GHz with excellent resolution. I'm sure that there are some who have done better. However, based on what I found, I am staying with my current configuration until the next generation systems are released. I am looking for, at a minimum, a comfortable 5 GHz capability.

I currently am running at 4 GHz, with my FSX settings maxed for my PC. I enjoy 20 plus FPS with smooth flight and excellent resolution just about anywhere in the world. For example look at the following screens taken from over and around LAX.

FPS is 31.8 and if you look closely you will see lights from people on the beach

FPS is 24.1 with aircraft taxing, aircraft on approach, and one aircraft about to take off.

FPS is 33.6 with a view of Los Angeles that mirrors the real thing.

Software running on my machine include but is not limited to FSGenesis, Megascenery, Ultimate Airport, REX, GEX, UTX, etc.

Regards,

Flight
Ace

When on FSX, open the task manager and watch your CPU usage. If it's quite high, that's your bottleneck.

bunky wrote on Sep 11^th, 2011 at 10:03am:


Skip,

Thanks for the tip.

I had thought that it might well be my GPU that was the cuprit holding back my performance. Because of this I added a couple of changes to my FSX CFG. The first was setting my Infinity Mask to 14. This changes core 0 to run only the fibers (scenery data, terrain textures, etc.), resulting in a more equal load across the remaining 3 physical cores. The second was changing my FIBER_FRAME_TIME_FRACTION setting from .33 to .20. This is the CPU time FSX devotes to loading scenery and textures. The default setting for FSX is.33. This variable determines the amount of CPU time given to loading scenery data as a fraction of the time spent rendering.

The result for me is going from 20 to 25 FPS flying from around LAX to 30 to 40 FPS circuling directly over LAX at 200 feet. And I might add a very smooooth flight with maxed out settings for PC.

And thanks to everyones' input as it does answer my original question as to a balance between GPU and CPU when it comes to one or the other bottlenecking. I believe that when an upscale CPU is running at 4 GHz or better and one experiences issues with performance, it's most likely to be the GPU that needs attention.

Regards,

Flight Ace