A lot of people posted that for FSX the 3570K is the better CPU, because it run FSX as fast as the 3770K, it's cheaper and runs not so hot as the 3770K.
The difference between the two is that the 3770K has 2GB more L3-cache and the possibility to use hyperthreading.
For FSX this is useless. So buying the 3570K would be the best choice.
But when Prepar3D goes to version 2 is this then still the best choice. Will Prepar3D version 2 make use of hyperthreading??
If so, is 3770K then the better choice.

Regards

Werner Verwaal

Thank you Zach for a very informative answer. May I ask please what you would consider the best settings for my i7 3960. Firstly should my HT be switched on or off and secondly what is the number of Processors I should select in the msconfig --> System Configuration --> Advanced options --> BOOT Advanced Options? I can, of course select up to 12. Many thanks.

Hey guys, I spent a little time looking at our affinity mask settings on my personal 3960x this weekend and I have some more solid answers for you. I'll start with the affinity mask, and then how explain hyper-threading fits in.

The affinity mask is a one byte ( 8 bit ) mask that tells our job scheduler which processors to schedule jobs on. If you have a 6 core processor with hyper threading, i.e. a 3960x, 3930k, etc., your processor has more cores than are covered by our bit-mask. Nevertheless, Prepar3d's default behavior seems to be to use one of the threads on each of the two extra cores. This is the desired behavior, so I see no reason to worry about it.

The reason that Prepar3d selects every other logical processor and many recommend disabling hyper threading entirely has to do with the way hyper threading works, as well as the type of tasks we thread off to background threads. Hyper threaded processors have certain select parts of their cores duplicated, which allow them to process two commands at once on a single processing core. That being said, they share the same components for accessing system resources like main memory and hard disk access. These resource access operations are very slow, and these are the primary tasks that we farm out to background threads. These resource access tasks perform very poorly when placed on both logical cores of a single hyper threaded processor core. Because the two logical cores share access to system resources, their I\O requests can interrupt one another, causing additional hard drive seeks and other very slow operations. For this reason, it does not benefit Prepar3d to use all of the cores on a hyper threaded processor, and doing so can in fact contribute to stutters.

My suggestion is to use the bit mask to map one thread to each physical core on a processor except for the primary core, which will almost always be I\O bound to begin with. I would leave hyper threading enabled at the system level because it does have benefits in general computer use and many other applications.

That is the same value I arrived at for the 3960x, because the bit-mask only works for the first 8 logical cores. The remaining four seem alternate by default, which means I run on core 2, 4, 6, 8, and 10. I believe that this is the optimal situation.

See my pic's here http://prepar3d.wordpress.com/2012/06/23/post-1324/

Hi Mac: If you have a 12 core...and P3D uses an 8-bit instruction to address the cores, the AffinityMask value = 84 >> 01 01 01 00
Read from right to left: the first core (thread 0 and thread 1) are not addressed and as such reserved for I/O instructions.
From the other cores ( 01 01 01) the HT threads are set to zero, which means that the thread is not addressed by the instruction for the P3D process.
Since in a 12 core processor the last 4 threads (00 00) are not addressed by P3D (which does not mean the are work-less for other processes...) the affinity settings in the prepar3d.cfg = also 84 >>00 00 01 01 01 00
Read the affinity stuff here http://janvaane.org/virtualfsx/?p=4