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CPU and GPU Performance: A Comparison between X-Plane 10 and FSX

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29 replies to this topic

#11
paullv

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has anyone tested XP with new GTX670 / 680 with 3 monitors?


GTX670/680 needs three identical monitors to activate NV surround....

I think their 2GB RAM will limit the performance of X Plane 10.

Two 3840 x 1200 resulution already eat up 1.6-1.8 gb VRAM.

#12
AndyGoldstein

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I think their 2GB RAM will limit the performance of X Plane 10.

Two 3840 x 1200 resulution already eat up 1.6-1.8 gb VRAM.

Do the arithmetic and you'll see that screen resolution has essentially nothing to do with VRAM requirements. The frame buffers are a tiny part of VRAM use. Most of VRAM is taken up by elevation mesh, shared object library, and mainly textures.

- Andy

#13
Thorax

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GTX670/680 needs three identical monitors to activate NV surround....

I think their 2GB RAM will limit the performance of X Plane 10.

Two 3840 x 1200 resulution already eat up 1.6-1.8 gb VRAM.


how did you make that calculation for vram consumption versus total resolution?

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#14
chris k

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3840 x 1200 x 4 bytes per pixel (RGBA) =~ 18 Megabytes.

~18 Megabytes of frame buffer / ~2000 Megabytes on the card <~ 0.9% of the VRAM.

The large screen takes less than ~1% of the Card's VRAM.

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#15
paullv

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3840 x 1200 x 4 bytes per pixel (RGBA) =~ 18 Megabytes.

~18 Megabytes of frame buffer / ~2000 Megabytes on the card <~ 0.9% of the VRAM.

The large screen takes less than ~1% of the Card's VRAM.

I Love Math! =)

- CK.


Well, I believe what's happeining in the real world rathyer than theory on the paper.

Here are my test results (GPUZ):

Single monitor 1920x1200, with HDR, FXAA.
Memory Usage - Dedicated: 1747 mb
Memory Usage - Dynamic: 110 mb
Attached File  fxaa single monitor.jpg   47.26KB   2 downloads

Two monitors (eyefinity) 3972 x 1200. with HDR, FXAA
Memory Usage - Dedicated: 1924 mb
Memory Usage - Dynamic: 94 mb

Attached File  fxaa two monitors.jpg   40.55KB   2 downloads




------------------------------------------------------------------------------------------------------

Single monitor 1920x1200, with HDR, 4SSAA.
Memory Usage - Dedicated: 1832 mb
Memory Usage - Dynamic: 72 mb
Attached File  4AA single monitor.jpg   42.25KB   1 downloads

Two monitors (eyefinity) 3972 x 1200. with HDR, 4SSAA
Memory Usage - Dedicated: 1996 mb
Memory Usage - Dynamic: 91 mb

Attached File  4aa two monitors.jpg   53.71KB   3 downloads


Please also see the results displayed by X Plane 10. They are different from GPUZ's reading, but show the same trend: you need more VRAM for multi monitors.

FXAA Single monitor: 1465mb
Attached File  fxaa single monitor.png   63.31KB   8 downloads

FXAA Two monitors: 1573mb
Attached File  fxaa two monitors.png   65.65KB   7 downloads

4SSAA Single monitor: 1630mb
Attached File  4aa single monitor.png   64.45KB   6 downloads

4SSAA Two monitors: 1938mb
Attached File  4aa two monitors.png   61.77KB   7 downloads


I think 3GB VRAM is necessary for three monitors.

Edited by paullv, 23 June 2012 - 03:27 AM.


#16
771416445

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Did u know according to Austin i7 extreme cpu can only run on medium setting on X-plane 10 and if you have multiple cpus you will see much more than a single cpu.

#17
AndyGoldstein

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Please also see the results displayed by X Plane 10. They are different from GPUZ's reading, but show the same trend: you need more VRAM for multi monitors.

Interesting results. Some of the anti-aliasing techniques use super-sampling, which requires an oversize frame buffer with 4x or possibly 16x the pixel count. Scale that up with multiple frame buffers and the space does start to add up.

One observation: X-Plane's description of the space required is "Total size of all loaded textures at current settings", which is not the same as total VRAM use. Unfortunately I don't know how they're measuring or computing that number. I did some brief experiments with just changing the window size (running in a single 1080p monitor), and compared the reported values with minimum 1024x768 and 1920x1080 windows to VRAM use as reported by my graphics card utility. With my settings (HDR off, 4x FSAA) X-Plane is reporting a 5MB increase in VRAM use, but the graphics utility is reporting 50MB increase. The graphics card utility is also reporting a substantially larger total VRAM use than X-Plane.

My guess is that X-Plane is computing an estimate of VRAM use, and it's not entirely accurate or complete. It's probably better to get VRAM use figures from a graphics card utility if one is available for your graphics card. (I'm running an MSI GTX 460 and am using MSI's tuning and display utility.)

- Andy

#18
FloB

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X-Plane 10
(HDR+FXAA; 16x Anisotropic Filtering; extreme texture resolution; world detail distance -very high; mega tons of objects; tons of roads)
GPU Load: 40-60%
CPU Load: 25-46%
Avarage FPS: 18-20fps in 3D cockpit; 20-25 fps without 3D cockpit.


It seems that X-Plane 10 failed to use the CPU and GPU efficiently.



Well I'm not sure if that conclusion is right. The GPU load indicator is much more tricky than people think. What the h### is the "load" of the gpu? A gpu is a complex build and in most cases some parts of the gpu are busy and others are not. Maybe the "load" is just the average of all parts. And you can't just take one for another. It's like riding in a car and complaining: My lights and whipers are off, why can't I go faster!?
What will limit your framerate is the weakest and most used part of your gpu. Period. And should they include unneccessary features into x-plane just to give you a fully "loaded" card? Nope.

And it's almost the same with the cpu. Set AI planes to 20, traffic to chicago suburbs, clouds to 100% and fly around a big airport for a couple of minutes and compare the results to backcountry flying on a sunny day...

Afer all I think it's not right to measure "efficiency" by those "load" scales. Problem is more complex and to produce comparable results I suggest to try the build-in fps_tests 1-3. Otherwise we will never know what's really going on on the "other side".

Cheers
Flo

PS: Looks like you ran out of vram. Turn down texture resolution to very high and enable "compress textures".

Edited by FloB, 12 July 2012 - 03:18 PM.


#19
AndyGoldstein

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FYI, paullv is no longer with us, far as I know. He got called on a series of trolling posts and left in a huff.

- Andy

#20
KitVan

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X-Plane 10
(HDR+FXAA; 16x Anisotropic Filtering; extreme texture resolution; world detail distance -very high; mega tons of objects; tons of roads)
GPU Load: 40-60%
CPU Load: 25-46%
Avarage FPS: 18-20fps in 3D cockpit; 20-25 fps without 3D cockpit.

It seems that X-Plane 10 failed to use the CPU and GPU efficiently.


I've read this thread and several others, but still can't find out why CPU utilization in XP 10 is so low, or how to improve it. While using XP 10, I consistently reach a place where my GPU is almost maxed-out, but my CPU is only being utilized at 20-40%.

I don't mind my GPU being maxed-out, but I'm wondering why I can't get XP to use the CPU resources that it has available. Ideally, I'd like to be adding more autogen etc. that uses the CPU.

My computer has a i7 920 overclocked to 3.3 Ghz, NVidia GTX 580, 6 Gigs DDR3 Ram. (Currently running Xp 10.10 beta 11)


Does anyone know why X-Plane 10 won't use more of the available CPU power? ...or better yet, how to make it?


Thanks,
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