Anyone tested P3Dv4 with Core i9-7900X

[Rob Ainscough]

I was able to work around the problem by removing my Sabrent USB 3.0 PCIe card I had installed. Apparently some incompatibility with ASUS PRIME X299 DELUXE ... ASUS have been notified.

I was also able to get the EZ-XMP switch to work with my RAM, had to do a MEMOk! reset (on motherboard) and a few reboots and now my G.Skill XMP profile is working correctly.

Here are some quick stress test videos I did at 4.8GHz and just a quick test to see if 5.0GHz would run, 5.0Ghz is probably going to need more actual OC configuration but all the 4.8Ghz testing was just basic OC stuff at low voltage.

https://youtu.be/rruCo5TwO8A

https://youtu.be/oC1ptZ78NbU

https://youtu.be/Tbk85Ev-FAw

https://youtu.be/8o--6dWRXno

I'll do P3D V4 testing later this week and post results.

Cheers, Rob.

[Rob Ainscough]

I posted my P3D V4 testing results here: https://www.avsim.com/forums/topic/5149 ... -increase/

Cheers, Rob.

[JPS2K5]

Meh... I'm still reluctant. My 7700K is running all cores on 4.6Ghz now, and P3D is running 'ok'. I'm kinda worried that I won't get enough cores kicked into turbo mode on a 7900x to match that.... :(

[Rob Ainscough]

No problems running all cores at 5.0Ghz on my i9 7900X, HOWEVER, because that runs at 80C under load even with water cooling, I back down to 4.8Ghz all cores. Perhaps when I move to a water chiller setup I'll go back to running at 5Ghz all cores.

I run fixed frequency so really have no need for "Turbo Mode" nor the Intel Turbo Boost Max 3.0 technology especially since that Intel technology appears to have a serious bug that triggers thread contention.

Cheers, Rob.

[JPS2K5]

Well, I bought one. Still figuring out how to keep it cool. It's running on 4.5 GHz and 1.24 Vcore and while stable I see spikes of 90 degrees. Performance wise so far I'm not impressed (coming from the 7700K @ 4.6 GHz).

[Onky]

Your GPU makes considerably more difference than your CPU. That's what you should be focusing on, really. Also, a G-Sync monitor can greatly help, as you can get rid of VSync in your settings AND eliminate any tearing (VSync=Off) or stuttering (VSync=On) at the same time.

Believe it or not, my rig is still Core i7 920-based, but that GTX 1070 (+GSync) is the one that is saving my a$$.

[JPS2K5]

That's a cool story, but my GPU is a 1080Ti and not utilised for 100%. I'm on 4K, I'm pretty sure you're not. When I say I'm not impressed I mean I see not much difference in performance. Although I don't really test, I just fly my regular routes, so weather differences might have some impact.

[toutenglisse73]

Hi JPS2K5,
If you want to make your GPU load approach or hit 100% (that will make it the fps limiter) the cursor to move or max out is Dynamic Reflections (in Options_Lightning). (shadows should be maxed out also but less impact)
About i9 7900x, it's Strange to see results as far as 85% faster than i7 7700K/i7 5960x....I'm ok with it cause it seems to be factual results but in other sim, xplane 10, 64 bits, the comparative results are totally different... of course the sim engines may be very different but what could be closer to compare ? So in this other sim if i9 7900x is 100% (in terms of FPS for an identical test), the i7 5960x is 117% and the i7 7700k is 167%.
http://www.comptoir-hardware.com/articl ... l?start=14
Famous french site (so hard to read for English people) but on this page this is the last graph (38 CPU compared on different applications).
No such test for xplane 11 but according to 2017 benchmark data single core/thread performance is still the best
https://docs.google.com/spreadsheets/d/ ... AI/pubhtml
Of course if Prepar3D v4 is really high multi-core user than this 85% faster for i9 sounds ok.
How about making a chart (with no addons...) to test and report lot of user's config with prepar3d ? This could have some interest ?

[Rob Ainscough]

It's running on 4.5 GHz and 1.24 Vcore and while stable I see spikes of 90 degrees.

If you're hitting spikes at 90C then you'll likely trigger thermal throttling. I can assure you the i9 7900X is considerably faster/better than the 7700K ... I have both CPUs and tested both, you should be seeing at least 85% increase in FPS with the 7900X.

Make sure you disable Turbo Boost Max 3.0, turn OFF HT in BIOS, disable SpeedStep, and provide the CPU with a good quality water cooling solution (recommend at least a 480 x 60mm radiator. No problems running at 4.8Ghz with this setup, I can also run 5.0Ghz but that run too hot at 80C so I'm staying at 4.8Ghz for now.

Cheers, Rob.

[JPS2K5]

Well, turned HT off, disabled SVID support and upped the digi+ VRM limit to 140%. Looks ok, temps are lower (makes sense without HT) and pretty stable, fps is up. Still places where I can drop to 45 (like YMMB) but overall I see an increase.

My watercooler is just a simple AIO Corsair H110i GTX 280mm, but per core it doesn't go higher than 80 now, so that's ok too.

[vince007]

Hi JPS2K5,
If you want to make your GPU load approach or hit 100% (that will make it the fps limiter) the cursor to move or max out is Dynamic Reflections (in Options_Lightning). (shadows should be maxed out also but less impact)
About i9 7900x, it's Strange to see results as far as 85% faster than i7 7700K/i7 5960x....I'm ok with it cause it seems to be factual results but in other sim, xplane 10, 64 bits, the comparative results are totally different... of course the sim engines may be very different but what could be closer to compare ? So in this other sim if i9 7900x is 100% (in terms of FPS for an identical test), the i7 5960x is 117% and the i7 7700k is 167%.
http://www.comptoir-hardware.com/articl ... l?start=14
Famous french site (so hard to read for English people) but on this page this is the last graph (38 CPU compared on different applications).
No such test for xplane 11 but according to 2017 benchmark data single core/thread performance is still the best
https://docs.google.com/spreadsheets/d/ ... AI/pubhtml
Of course if Prepar3D v4 is really high multi-core user than this 85% faster for i9 sounds ok.
How about making a chart (with no addons...) to test and report lot of user's config with prepar3d ? This could have some interest ?

Hi dear French neighbour,
I'm agree with JPS2K5, my SLI of 1080 is use only at 30%. I will try your suggestion about dynamic reflections to increase the use of my GPU.
But my cpu, an I7 6950 oc to 4ghz is still between 25%...
So, when i play modern video game such in 4K, Far cry, ghost recon, battlefield, or any other game in VR (robot recall, valkyrie VR) etc, i use 100% of my GPU in SLI, and around 20/25% for my cpu.
Ok, it's not the same game, but, for example in 4K, everything parameters at the maximum, ghost recon wildlands is much more better visually!
Does it come that the engine behind prepar3D is an old engine which came from FSX?
Regards.
Vincent

[toutenglisse73]

Hi Vince007,
yes Wildlands is really cool and well uses multi-core cpu's, on my i7 all 8 threads have high usage.
In p3dv4 if your cpu has a 25% usage it's a global usage, in fact you have one core/thread at least that is in high usage (near 100% I guess).
P3dv4 is able to well use the ressources you have - it's just a matter of setting well the gpu-heavy and the cpu-heavy options, so both cpu and gpu are well used and one doesn't bottleneck the other.
With good settings, using oculus rift, P3dv4 runs with near max load for gpu and 4 cores highly used with 1 really near max all the time (hyperthreading off) - rendering stable 90fps vsync in rift (monitoring all this with afterburner). At least for me and my specs.

[srce]

Is there an advantage for P3D in comparison to an i7-4core CPU?
The 7900X offers 10cores @4,3GHz in TurboBoost. Can P3D use 10cores or are 6 or 8 enought?
What is with an i9-7980XE with 18 cores?

Here's a typical CPU load with an i9-7980XE with core 0 at 4.8GHz and other cores at 4.2GHz.



There are a couple of caveats. FPS largely depends on the main p3d thread, so I've used AffinityMask to disable CPU 1, to avoid any hyperthreading conflicts with CPU 0, which runs the main thread. However, as per this thread: viewtopic.php?f=6312&t=127453 the AffinityMask appears only to be 32-bit, so you can't use all 36-CPUs. (Although you probably don't want to anyway, as if all cores get fully loaded, it would throttle CPU 0).

I suspect FPS is determined by performance of CPU 0, but perhaps texture loading time etc is improved by having multiple cores. The latter is tricky to measure though, so it's just a guess. Extra cores definitely appear to be used - but it's hard to know what's the best tradeoff between max frequency and number of cores. Fortunately, this seems to have pretty decent single thread performance too.

[supersonic_80]

Is there an advantage for P3D in comparison to an i7-4core CPU?
The 7900X offers 10cores @4,3GHz in TurboBoost. Can P3D use 10cores or are 6 or 8 enought?
What is with an i9-7980XE with 18 cores?

Here's a typical CPU load with an i9-7980XE with core 0 at 4.8GHz and other cores at 4.2GHz.



There are a couple of caveats. FPS largely depends on the main p3d thread, so I've used AffinityMask to disable CPU 1, to avoid any hyperthreading conflicts with CPU 0, which runs the main thread. However, as per this thread: viewtopic.php?f=6312&t=127453 the AffinityMask appears only to be 32-bit, so you can't use all 36-CPUs. (Although you probably don't want to anyway, as if all cores get fully loaded, it would throttle CPU 0).

I suspect FPS is determined by performance of CPU 0, but perhaps texture loading time etc is improved by having multiple cores. The latter is tricky to measure though, so it's just a guess. Extra cores definitely appear to be used - but it's hard to know what's the best tradeoff between max frequency and number of cores. Fortunately, this seems to have pretty decent single thread performance too.

Hi, wouldn't it be better if you use a Affinity mask where you disabel CPU 0,1 and 3? So Win can use Core 1 and P3Dv4 has the full Core 2.

[srce]

Why does Windows need Core 0 free? It seems to be scheduling programs on the higher numbered CPUs in the picture above. Is there something it runs only on Core 0?

Having said that, there is another reason not to use Core 0 for the main thread. For CPUs that support Turbo Boost 3, Core 0 may not be as fast as some of the others. In my case, Cores 7 and 8 are the fastest. Unfortunately, there doesn't appear to be away in the .cfg file to say which core/CPU the main thread should run on. However, this can be worked around by manually changing the affinitymask in windows task manager after p3d is running, to just put all threads on the fastest CPU, then change it again to spread over all CPUs (although this is a bit of a pain).

If I do that, and bump up the p3d settings with a few addons used, all those cores are getting used:



Here CPU 14 is maxed out with the P3D main thread. Just need to find a way to stop Windows from scheduling anything on CPU 15.