GPU Upgrade or CPU

Any issues, problems or troubleshooting topics related to computer hardware and the Prepar3D client application
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Physics70
Posts: 29
Joined: Tue Apr 11, 2017 7:21 pm

GPU Upgrade or CPU

Post by Physics70 »

Hi.

I would like to ask your opinions. I am running P3D V4. I have an i7 4790K OC at 4.6 GHz and a GTX 1060 GPU. When I run P3D V4 on one monitor I am getting anywhere from 45 to 72 FPS. Even on a highly detailed airport I am getting frame rates around 38 to 42 FPS.

However, like you I run my simulators across 3 monitors. If I am getting 34 FPS on on monitor, it drops to anywhere around 17 to 24 FPS. Now that is not bad, however, I would like to average around 25 or better. I am pondering an upgrade. It seems to me that if I am getting great frame rates on one monitor, my problem is not he CPU but rendering. Should I be looking at getting the 1080 GTX Ti FE? I don't want to spend that kind of money and get negligible results. Does this look like a job for a GPU upgrade or CPU upgrade. I can do one, but not both.
MHargrove
Posts: 251
Joined: Sun Dec 18, 2011 9:08 pm

Re: GPU Upgrade or CPU

Post by MHargrove »

Physics70 wrote: ...
It seems to me that if I am getting great frame rates on one monitor, my problem is not the CPU but rendering.
...

That's an invalid conclusion, especially if you're placing undocked windows on the other two monitors. The CPU has to do a significant amount of additional work to drive those extra windows. Yes, the GPU helps out (quite a bit for some of the rendering), but you're still almost certainly CPU-bound.

Here's how to tell for sure:

- create your three windows, one on each monitor
- bring up your frame rate display, and note the FPS value
- now make all of your windows very tiny
- if the FPS increases when you make the windows small, you're GPU-bound. If not, you're CPU-bound.

Another way to see this is to bring up Resource Monitor and watch the CPU0 resource graph (assuming you're using the default affinity mask). You'll note that CPU0 is pegged at 100% regardless of how big or small the windows are. Indeed, if you close the two undocked windows and make the main window very tiny you'll see that CPU0 is *still* pegged at 100%.

Right now, even with v4, single-core performance is the ultimate bottleneck for Prepar3D. The only way to improve things is to reduce settings for things that are CPU-heavy.

-M.
Mark Hargrove
Longmont, CO
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