Hi,Was just curious about this as I know this is left off with FSX.Bob

XPX might need hyperthreading on, I'd also like to know.

FSX didn't thread well with more than 2 or 3 cores being used more than 50%. HT didn't make a bit of difference and the extra heat generated wasn't worth it. XP10 is supposed to be better at utiling multiple threads, so turn it off, see the CPU usage, reboot, turn it on, and check the usage again. It would be good to see if there is much difference at all.

I turned mine on and saw the virtual cores being used more and fps improved.

Thanks Simon, I'll give it a try then.

The problem is: i had to disable HT due to my overclock on my I7-860. So does XP run better on default stock speed (2,4) with HT on = 8 cores or CPU oc'ed to 4.0 with HT turned off meaning only 4 cores?

I don't know but I wont put my OC down to turn on HT. I dont see all four cores near 100% at any time but I do see one core at 100% occasionally so I will keep 4 cores with OC. Also other games I have do better with OC than cores and I dont want to keep changing the bios for every game.

I have my chip overclocked conservatively to 3.8 with ht on, and the sim runs very well. CPU is not pushed as a lot is moved to the gpu, but I hope ben reviews the stats once he gets around to serious optimising

If I got this right XP will use one core for each AI plane so my 6 core will be able to handle 6 AI plane without HT on, if I turn HT on I will be able to use 12 core for 12 AI plane.....XP as 20 AI plane.Up to you guys to see if the XP will run as good (smooth) with less overclocking but more core, HT on is not good for FSX DX9, FSX DX10 is another story.

Alain, I've found the AI don't use that much of the CPU, so I see only small use of all 8 virtual cores but can run 20 AI nearby.

My point was more core = better perf. in XP-10 since the workload is devided between more core...

I still dont understand the AI plane + core story. I set my plane at pos. X at an airfield. 15 planes are inactiv at gates. 5 are pushing back out of my field of view cause of building obstruction. 3 are taxing near my vicinity, 5 are in a holding pattern for landing which i only see 1 in the approach. How much planes will Xplane dedicate to a core?

Austin apparently went overboard when estimating how much processing ability the planes would actually take up, but, to be fair, he also said that due to the multi-threaded nature of XP10, you could increase the # of AI to a number capable of using any available processing space left on your multi-core CPU. The flight model doesn't take up a whole core, which is good news. My limitation on my i5-2500k 4.8gHz tower is my 9800gtx cards not putting up with all the fluff on the screen all the time. I get decent frames, but when it comes to a urban area with clouds and aircraft, it gets a bit slow. Dial back the clouds and I'm back to good. But the AI take more processing time to DRAW than to calculate their behaviour flight model-wise. We may be able to get over the 20-AI limit pretty well considering the limited processing space of the FM. The trick is to also integrate the ability to have realistic AI (not just random, but realistic aircraft types with maybe timetables - barely any aircraft active at 0200, lots at 0600 just before the 0640 departures, the conga line of aircraft all trying to depart the same runway at the same time and the mass of arrivals all with similar arrival times). I see great promise in the FM not taking up so much headroom CPU-wise, just need to flesh out the other side of things and it will be excellent indeed. Then get some AI models specific for this function and let them loose into the world.

Hi,Was just curious about this as I know this is left off with FSX.Bob

So, with all this discussion, what is the answer/suggestion to the question? HT=ON or HT=OFF ?

Right now, I don't think HT on will mean much of an increase. Most things are GPU fill-rate limited rather than CPU limited. When the time comes to allow more aircraft and other AI advancements, it may be prudent to turn it on when your CPU usage hit 80% or better across all cores.The best thing to do, though, is try it. Load up your aircraft in a particular airport and fly around a busy area with max aircraft and vehicles you can sustain decent flight with. Minimize non-CPU items (like objects/bulidings/HDR) to improve FPS. Watch your FPS and see the general performance.Now reboot, turn on HT and repeat the flight with the same settings and see if there is ANY improvement at all. If there is, you know it does something for you. You may be able to run full vehicles and AI aircraft with HT on (CPU calculates what path they take and how their vehicle gets from A to :( but if you turn up your other graphics settings back to previous values, you may not be able to DRAW all of them in addition to the extra objects you had to turn down.If you test it, let us know your results. It could be most enlightening for those thinking about sticking with an i5 like myself or upgrading to the i7 for the extra cash.