I have a question for the experts regarding Hyperthreading.
When enabled does Hyperthreading in an unclocked Intel Ivy Bidge i7 Processor with Windows 7 64 bit OS actually slow down FSX ?
Or does it not matter remembering we're talking about an unclocked system.

Regards,
Donair

I'm not 100% sure of the question you are actually asking, or more the reasons for you're asking it, but I'll give it a go.

 

FSX was originally designed around a single core CPU, multi core support was tacked on in Service Pack 1. However the main sim engine is still restricted to a single core, any remaining cores are used solely for texture rendition and autogen. As the main sim engine has to allocate and impliment the work done by the other cores there is a slight overhead for each individual core used. So in terms of slowing down FSX each additional core you use whether physical or virtual will impact on FPS. Also consider that when using hyperthreading the physical cores will have the overheads of the work assigned to the virtual cores as well as their own workload so they wont be able to perform to the same levels.

 

However FSX is not all about FPS (unless yours are really poor) and utilising additional cores both physical and virtual to assist with the rendering of textures and autogen (at the cost of FPS) can make for a smoother and more enjoyable flight experience, and there are ways to reduce the impact of having HT enabled. Because peoples hardware, requirements and expectations differ there is no one-size-fits-all answer to "HT on or off" or the best way to control FSXs use of cores through the AffinityMask setting, but you will probably find reading through the following thread worthwhile - http://forum.avsim.net/topic/402292-fsx-hyper-threading-or-not/