P3D V4.5 settings and Scenery

[GSalden 4,657]

1 hour ago, SteveW said:

Having spoke about this with Gerard and some others, and testing here, the feeling is that for a big system you might need ten or more cores with P3D on eight of them.

That is correct.

I can fly everywhere with heavy scenery + bad weather and 8 cores (= HT cores ) is the best with my 14 core 7940X.

Only when it comes to TE Great Britain London city + AS Heathrow + AI traffic + bad weather, only then I use all the 14 cores...  I have monitored all cores without an AM and used the 6 less taxed cores for my cockpit Addons. 
Now I can fly over London city at 220 knots and have no stutters ..  I use the Lecacy Intel Turbo Boost that puts the main P3Dv4 thread into core 8 and then chooses the rest of the cores from strong to less strong for the rest. And that is not 9,10, 11 etc but purely chosen on strength.

Thanks to Steve who advised me to monitor the cores I was able to “concur” TE GB London with Very Dense AG/SC...

😎
 

Edited January 12, 2020 by GSalden

[SteveW 1,792]

10 hours ago, Noel said:

I'm actually very comfy...

Yes, I understand that. My worry is that some might observe your comment to mean use them all works best.

My posts are not aimed directly at any one person, my posts must be viewed as general advice for all situations and system specifications.

 

We see lots of posts regarding AMs and HT, whereby the comment goes something like "I tried an AM / HT and it was worse". That's not because HT and AMs make things worse, they make thing better if you know the limitations. Neither can they fix problems in the sim with setup and will likely make matters worse in those circumstances.

Here's the thing; take an average video encoder. Simplify what happens, we have an organising task that assigns one frame per core. With 16 core CPU we get the movie conversion completed in a bit more than half the time of 8 core CPU on that same motherboard. We can keep adding cores and we complete the movie more quickly. However, the time per frame reduces as we go because they all draw on the same limited resource. Not much of a problem because we don't care how long each core takes, so long as more cores complete the total job faster.

P3D is no different in the background task. We can keep adding cores and we go on seeing decreased loading times and higher fps. Keeps improving. What the real problem is, is that the overall drop in per core performance is what affects the main P3D task as well - it is not exempt from other task's demands. We don't want that aspect of multicore performance as it upsets P3D. So we are facing a compromise.

Gerard confirms this fact. He can use 14 cores but when he has the full sim going he must reduce that count because overall system throughput being over-absorbed causes stutter.

What about when we load more dense scenery? We know it takes longer to load. Even though the sim main task continues with the same fps, it is the overall draw on the system that reduces the performance in the way the main task receives the information unsteadily to cause the slowdowns and stutter.

Edited January 13, 2020 by SteveW

[Dirk98 354]

I understood Gerard as saying that in the most demanding scenery and wx conditions he had to engage all 14 cores for Prepar3D.exe to attain a decent performance. Did I read him wrong? Was it still 8 cores for Prepar3D.exe? I still think he said all 14 cores to P3D when scenery and wx were unbearable. 

Thanks.

 

[SteveW 1,792]

That's the balance he found when he has it all going.

[SteveW 1,792]

...seems better to have less cores more engaged, than more cores less engaged. Say 8 at 80% each seems better than ten at 64% each.

[Dirk98 354]

1 minute ago, SteveW said:

...seems better to have less cores more engaged, than more cores less engaged. Say 8 at 80% each seems better than ten at 64% each.

That was my understanding until I read Gerard's post above.

Btw, what is Intel Legacy Turbo Boost? Is it a software?

Thanks

[SteveW 1,792]

Turbo boost is the intel software handling the core speed and power, installed by windows, he's using an older version. What Gerard told me was he found consistently better to have 8 cores for overall performance most of the time. I mentioned the sim loads faster and fps creeps up (only slightly) as cores are added, so in theory it appears we need ever more cores. However, looking closer at what's going on there's system resources invoked when the sim makes demands. Those system resources communicate with addons and handle file and network and so on, and they run on the sim cores. When the sim occupies more cores the demands momentarily push out the resources it is waiting for.

[GSalden 4,657]

1 hour ago, SteveW said:

Turbo boost is the intel software handling the core speed and power, installed by windows, he's using an older version. What Gerard told me was he found consistently better to have 8 cores for overall performance most of the time. I mentioned the sim loads faster and fps creeps up (only slightly) as cores are added, so in theory it appears we need ever more cores. However, looking closer at what's going on there's system resources invoked when the sim makes demands. Those system resources communicate with addons and handle file and network and so on, and they run on the sim cores. When the sim occupies more cores the demands momentarily push out the resources it is waiting for.

Steve is right.

Only the London scenario uses all cores : main thread 100% and the others 70-100 with most of the time 82-84%.

Keep in mind that I am using very high settings and one 2-monitor view @ 2x 4K...

[SteveW 1,792]

looking at the CPUs usage and AM0 (all cores) I'm seeing every core combine to do the background work, for a short time. With less cores, I'm seeing the same work, but taking longer. The other cores continue to be used as they do system work. The main task shows less interference as that happens. So I've been testing the stock sim and medium to high settings, turning a circle inside thick clouds with dense scenery below. Strictly repeatable system ensures the same flight, clouds, AI each time. I'm seeing 8 cores for the sim and two for addon exes as really fine and smooth. More cores seems to mess the system around a bit, with HT enabled and the sim on 1 LP per core. With heavier scenery it doesn't seem to help adding cores. Turbo boost works on tasks that don't consume much throughput. When the sim runs, with its high demands, the CPU throttles most of the way up and not much can be done other than let the sim have what it wants.

[Noel 4,502]

3 hours ago, SteveW said:

...seems better to have less cores more engaged, than more cores less engaged. Say 8 at 80% each seems better than ten at 64% each.

FWIW with 12LPs in any kind of complex scenery I often have the 8 of those available for scenery loading bouncing between 80 and 100%.  Here's one:  if a whole core is showing 100%, and we split this core into two LPs, and both of those two LPs in the exact scenario show 50% utilization, is that the same amount of processing happening as the one whole core at 100%? 

Edited January 13, 2020 by Noel

[SteveW 1,792]

26 minutes ago, Noel said:

FWIW with 12LPs in any kind of complex scenery I often have the 8 of those available for scenery loading bouncing between 80 and 100%.  Here's one:  if a whole core is showing 100%, and we split this core into two LPs, and both of those two LPs in the exact scenario show 50% utilization, is that the same amount of processing happening as the one whole core at 100%? 

But remember with HT LPs, those pairs share one core. So with 100% on both that is still only 100% of one core, they each have 100% of their share.

[SteveW 1,792]

..if you simplify things and look at just two threads, they finish a little bit sooner on an HT core one per LP, than they do both placed on the one non HT core. So in effect it's a bit more possible throughput when used correctly. Problem is we don't want any sharing HT or not when it comes to the main task. Background tasks can share and extract a little more from the CPU. More work  = more heat so always set an overclock down the curve a bit to allow for extreme use of the cores.

Edited January 13, 2020 by SteveW

[B777ER 2,486]

On 1/9/2020 at 8:10 PM, Noel said:

Wake me up when someone with a 9900K can comment on HT on versus off that is my only question.  

I never have blurry anything and don't use any custom FFTF setting, but I use a 6 core w/ 12 LPs per HT enabled.

I have a 9900k. Don't use HT on mine. I just go in after P3D starts, right click on the exe in the details tab, select set affinity and click okay. This spreads the load of P3D pretty even across all 8 cores. Otherwise, Core 0 is pegged at 100%.

[Dirk98 354]

4 hours ago, GSalden said:

Steve is right.

Only the London scenario uses all cores : main thread 100% and the others 70-100 with most of the time 82-84%.

Keep in mind that I am using very high settings and one 2-monitor view @ 2x 4K...

Gerard, to make it 100% clear, when you fly into London what Prepar3D.exe affinity do you use?

Thanks.

[GSalden 4,657]

4 minutes ago, Dirk98 said:

Gerard, to make it 100% clear, when you fly into London what Prepar3D.exe affinity do you use?

Thanks.

Hi Dirk,

Then I use no AM at all.

regards, Gerard