Some time ago, I posted this below, over at AVISM
I have today installed TP into my new, fresh FSx installation. Over the past week, I have been "tuning" FSx and have read a lot about so-called"tweaks" for FSx. It appears that most of these were in fact developed before SP1 was issued and it seems that some are no longer of any use. In fact they may even be detrimental. It also seems that your success or otherwise in running FSx is dependent on a number of things - which some of these tweaks interract with in a negative way . 2 of these "things" relate whether you have a dual core or single core machine - and also to what amount of vid RAM you have.
I note that installation of TP makes some changes to the FSx.cfg file
1. TEXTURE_BANDWIDTH_MULTI is changed for 40 to 400
2. FIBER_FRAME_TIME_FRACTION goes from default 0.33 to 1.33 (with a note in the installation folder to say that if this is too sever, then go back to0.66)
3. BUFFERPOOLS goes from default 4 MB to 5MB
From Phil Taylors' ( MS) blog is this info relating to each of these:
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TEXTURE_BANDWIDTH_MULTI
The TEXTURE_BANDWIDTH_MULT option in the Graphics section is the target frame rate use for calculating texture bandwidth. The higher you set this value the more textures we will allocate and copy per frame to the graphics card. The lower you set this value, the less we will allocate and copy up to a minimum limit. As an example, the default rate in the “high” perf bucket setting is 40. The lowest perf bucket setting is 10.
Higher settings on this flag can cause stutters on frames where the terrain system has finished compositing lots of textures. Lower settings can reduce stutters on busy frames and spread out the load across multiple frames
So thinking this thru, if the value you set is 40, and your frame rate limit is 30, then we will send 40/30 or 4/3 as much textures per frame.
Moving this value to 400, like I have seen some users post in the forums, is probably *not* what you want to do since that increases the texture load on the graphics card by 10x, eg 400/40 = 10x. And after talking about this to Raf, setting it to 0 is ignored and can be validated by setting it to 10 which should give no different results.
FIBER_FRAME_TIME_FRACTION
The operation of FIBER_FRAME_TIME_FRACTION on single core machines has not changed since RTM.On multi-core machines in SP1, we moved many fiber jobs off of the primary thread and onto secondary threads. Since FIBER_FRAME_TIME_FRACTION only affects scheduling of jobs on the primary thread, it will have less of an impact on the performance of Flight Sim on multi-core machines. In fact, we moved so many jobs off of the primary thread that there probably isn’t enough fiber work left to soak up the full time allowed by the default value of 0.33.
Therefore, on multi-core machines, there’s very little reason to tweak the fraction because it really only impacts performance of single core machines.
BUFFERPOOLS
The pedestrian sounding BUFFERPOOLS is a section of its own in the fsx.cfg file. There is a setting in there called Poolsize, as in
Poolsize=n
Where n is the amount of bytes we will allocate for one pool of vertex and index buffers to store geometry.
In RTM, the default setting was 1MB (1000000). The lower this number, the more pools the allocator will have to rummage through to find space for buffers and the more stutters you may have. In Sp1, we raised the default to 4MB (4000000) and optimized the underlying algorithm for finding free buffers
So be careful here, making this smaller can hurt you, since searching for space takes time and can cause stutters, and making the number too large can waste space. 4-10m is probably the range to be thinking about using unless you have a very high memory graphics card (>512mb )
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This is all very "theoretical" - but in my case, I have a Dual core CPU ( so the bit about the FIBER_FRAME_TIME_FRACTION is relevant to me) and I also have only a 256 MB vid card (which struggles) so the bits about BUFFERPOOLS and TEXTURE_BANDWIDTH_MULTI are also relevant to me.
At this early stage, I have started using TP with FSx using my FSx.cfg file as set up for "normal" non-TP use. It seems to be working quite well like this.
So, I would encourage everybody to have a think about the above in relation to whatever machine you have
I now run my FSX.cfg stock standard - using only slider control from within the Sim
I have yet to find any FSX.cfg "tweak" that really achieves anything in the way of improving my medium systems performance.
Barry