ONE TWEAK TO RULE THEM ALL :lol: Like so many of you, I spent more time tweaking and staring at the start-up screen in FSX than actually flying. When I first installed Prepar3D a few weeks ago, I tried so many different ’tweaks’, each proclaiming to be the ‘silver bullet’, the ‘one true setting’, the ‘holy grail’ for perfect visual fidelity and smooth flight. The truth was that none of them worked. They all resulted in blurred ground textures, caused stuttering or made the simulator crash. The problem with all of these ‘holy grails’ is that what works for one person won’t necessarily work for another because we all have a unique combination of hardware and software.   Q. If all that you need to make Prepar3D shine is the correct Affinity Mask setting, how are you supposed to figure that out?

STEP ONE - USE TASK MANAGER   Before you start, remove any [JOBSCHEDULER] AffinityMask=xxx entry that you might have made in your Prepar3d.cfg file.   Using Task Manager with Prepar3D running in window mode, I can see the computer activity on the eight cores of my cpu, from the left 1,2,3,4,5,6,7,8. I have a quad core cpu with Hyperthreading enabled, so I see eight visible cores in the CPU Usage History.  
Looking at the image above, I see a lot of activity on core 3 and a bit of activity on cores 5 and 7. This means that Prepar3D has a preference for those cores on my set-up. Your Task Manager will probably look completely different, it all depends on your unique set-up.

I also see minimal activity on cores 1 and 2, which indicates system activity, so I will reserve these two cores, as well as core 4, for the system and other programmes and assign cores 3,5,6,7 and 8 to Prepar3D. 5 cores is plenty for Prepar3D and 3 is fine for the system and other programmes.   STEP TWO - CALCULATING THE AFFINITY MASK VALUE

I won't try to explain the Affinity Mask setting in detail but you assign the cores backwards using binary code to generate a decimal value.

In this case I want to assign cores 3,5,6,7 and 8 to Prepar3D.

From the above, you can see that this equals 11110100 in binary.


1. Open the Windows Calculator
2. Click the radio button 'Bin'
3. Click the radio button 'Word'
4. Enter the value which describes the cores you want to use, in my case 11110100
5. Click the radio button 'Dec' and note the decimal number that appears, in my case 244.


6. Open C:\Users\USERNAME\AppData\Roaming\Lockheed Martin\Prepar3D v2\Prepar3D.cfg and enter the following at the top.


244 is my unique value and your value might be the same but if it is different, it does not matter as long as you used the Task Manager to figure out which cores to assign to Prepar3D.

7. Save the Prepar3D.cfg file. 8. If you have an Nvidia Graphics Card, go to Step Three, if you don't, you're ready to fly!


If you have an Nvidia Graphics Card, enable Adaptive VSync. Selecting Adaptive in Nvidia Inspector will not have the same effect as using the Nvidia Control Panel to set it.

1. Right click on the desktop and select NVIDIA Control Panel
2. Under Manage 3D Settings, select the Program Settings Tab
3. Select Prepar3d (prepar3d.exe) from the drop down menu
4. Scroll down and set Vertical sync to Adaptive
3. Save and close the Control Panel
4. Open Prepar3D, start a flight and under Options>Settings>Display>Frame Rate Controls, check that VSync is Off and that Triple Buffer is unchecked.
5. Enjoy your flight

Read more here:



If I fly in bad weather with AI, road traffic and cloud shadows over detailed scenery in a complicated aircraft, I am asking for trouble and my performance will suffer as a direct result. There is no magical setting but there is a computational limit to what our hardware can process in realtime. In five years, maybe the hardware will have caught up with the software. I hope so.

I cannot be held responsible for any adverse effects that might arise out of the use of the information presented above. It is presented as is.
This document is dedicated to Mike Greenblatt who taught me the importance of unification and gave me the tools I needed to get started.


  My Hardware
i7 4700k at stock speed 3.5ghz
8 GB DDR3 1600mhz Ram
Windows 7 64 Bit on 256 GB SSD
Prepar3D and all add-ons on 1TB WD Blue HD 7000rpm
Corsair RM 650w PSU Dell HP ZR30W monitor at 2560x1060 TM Warthog HOTAS
Saitek Combat Pedals and Throttle Quadrant

My Settings Prepar3D v2.2