I would like to share this experience for my own as well as others potential learning experience as one overclocks their cpu higher with some current cfg file settings. I think I know what I am talking about but maybe I do not so anyone feel free to correct me here. I am about to share my experience flying the NGX into Aerosoft PANC with UTX and REX and a bizzilion other things to bog down FSX as I reach higher and higher cpu clocks. You can look at my rig below and you will find my graphics card is the weakest link here.

 

Anyway I have been playing with Bufferpools for quite some time now and found Usepools=0 was to unstable so I went with RejectThreshold=131072 for a while. So we have this size of a bufferpool to "hold on" to data that a fast (or any) cpu spits out to meter into a video card and all above this number goes strait to the card. My 460 is a 1gb card but bufferpools=0 is to much for it and I believe this is more and more the case as cpu clock speeds increase, same goes for lower reject threshold values as well.

 

This was the first time I have ever experienced what happened today, this bad anyway. So there I was today descending into Aerosoft PANC today with some heavy REX cumulus over the mountains. All was super smooth until I hit the clouds. I started to get the stutters and low fps and figured as usuall it will be a passing thing. As I was 10 out from Big Lake VOR performance became much worse than usual, In fact things were unflyable. So I figured it may have been the occasional bug I have where I have to Alt/Enter and toggle to windowed and back to full screen and all would be fine again. When I did this all the graphics went negative, like the film negative. Just crazy this was so I toggled back again and everything reset itself and I had my scenery back again. As I was turning over Big Lake for ILS 15 final approach when big spikes shot up from all the trees and just stayed there allowing me to fly through them. What a sight this was, not only did I get crazy stutters but green spikes as well. Then the desktop showed up all of a sudden, and then FSX, and then the desktop, and then FSX. I continued onward toward the runway knowing a crash was imminent, and not of the airplane either. Then the hard lock for 5 minutes and CTD.

 

So I pondered why this happened when all was going so well for me in FSX for a while here and I came to this conclusion. With my slower video card(relatively to my system) as I began overclocking from my normal 4.6ghz cpu speed of the last 6 months to 4.7 and then 4.8 I think my RejectThreshold in the cfg file needed to go up. So the main bearing on stability using bufferpool tweaks is the cpu to gpu processing speed ratio. The gpu has to eat it as fast as the cpu is feeding it, or close anyway. I retested this area in the NGX again with RejectThreshold at 350000 and so far so good. Although this happened after 3 hours from Kelowna and I doubt it is something I can adequately test outside of another real flight to somewhere graphics intensive again but I think I am on to something here. Until I get that GTX 580 I am going to need a higher RejectThreshold OR untill I lower the clock on my cpu. This is something I am not willing to do unless un fixable problems crop up because of it.

 

So that was my learning my experience lesson today and I feel like I really understand this Bufferpools thing now.

You could try the same flight again if you were using real weather and can replicate it as you can with Active Sky.