Classic British Flight Sim

TSR2 wrote:... there are actually only 4 and if memory serves FS can only use real cores, hence 4 in use and the 4 hyper threads not...

Ben, Mike,
I'm not at all sure about FSX only using real cores as I've never seen that comment before. While it may be true, I've read an awful lot of posts about using different affinity mask settings depending on whether or not you've set your CPU to use hyper-threading. What is true is that FSX can only use four cores at most since it is coded with just three threads and a thread handler thread - and that's only with SP2 or Acceleration (prior to those being released FSX only used a single thread). If you set the mask to use more than four, or even use an external tool to achieve the same effect, then you may temporarily get better performance from FSX but you're also increasing the risk that it will suffer from stutters at best to CTDs at worst. Unfortunately, there are an awful lot of forum posts around the world where misguided users have described their experiences and posted their settings in an effort to help others - as long as their settings work for them, good luck to them, but it doesn't help to have these misconceptions left for all to find.

FYI, the most practical affinity mask setting is 14 for any CPU with four real cores - if you have a CPU with two cores AND hyper-threading then it would be a different value, but i don't have the calculator handy at this time to work it out. Jesus worked that out way back in 2007 / 2008 and nothing has happened since to change that determination - after all, the FSX code hasn't changed, has it. Sometime between then and when I retired, i wrote a simple guide to understanding this subject over at SoH, which it seems has gone walkabout - probably because of my arguments with their admins. However, there is some good advice from Jorge and myself to be found in this 2010 thread over in the Orbx forums - if of course you're interested in taking this further. I suspect you'll need to be registered with their forums to be able to read it -

http://www.orbxsystems.com/forum/topic/22252-tir4/

Hope that helps,
Ro

Ben said:
I'm guessing the CPU you are using has hyper threading. If this is the case, then there aren't really 8 cores, there are actually only 4 and if memory serves FS can only use real cores, hence 4 in use and the 4 hyper threads not.
If you do have 8 physical cores, then it may be your using the wrong cpu mask in your cfg file.
Which cpu do you have?
Holy moley! How do I find out whether I really have 4 or 8? I have the original book on the motherboard outside. Do I look there, or ask the computer to tell me, please?
I also didn't know there was a cpu mask, hang on, I'll look at FSX.cfg I have "show hidden files" selected, but the search can only find references to this file; when I go to My Docs etc as instructed, it finds nothing.

Ro
I am registered at ORBX, but gauging from my experience thus far, it may be beyond me, at least right now.

DaveB, hi mate,
Thanks for the info and pretty pictures

Just looked into W7 System info, and I see that there are 4 cores and 8 logical processors, so I guess that answers a lot.

Mike,
since this is Dave's thread, I'll not go into details about finding and checking your fsx.cfg file here. If you want to take this further, let me know and I'll explain how to check for an affinity mask setting and what it should be depending on your CPU.

Best,
Ro