Opinions on cpu for FSX?

[gandofalcon]

http://www.venetubo.com/fsx.html, visit this page and fun

[AK Mongo]

http://www.venetubo.com/fsx.html, visit this page and fun

Just used this for my old machine, let's see how it works. It seems too good to be true!

[vyper883]

Check out this thread at FDS:

http://www.flightdecksolutions.com/f...pic.php?t=4205

John

Incidently, that is MY thread on FDS LOL

[vyper883]

Thanks for the fantastic response.

VYPER883, so if you have 6 cores, you want to use 5 cores? The setting should be AffinityMask=16?

Matt Olieman

Hi Matt
No, it's a binary value. AffinityMask=16 would tell FSX to use JUST the 5st core, as fiber scheduling is tied to the first core, so would everything else You would have five unused cores, which is NOT what you want. In Binary (think of it as an on=1 off=0) but the binary values are inversed a value of 16 would look like so: "10000" (on off off off off off) when in reality core function-wise it would be (off off off off on) The binary value would be read right to left. A good example is here:

DECIMAL VALUE----------------BINARY BIT MASK-------CORES IN USE
1------------------------------------00000001-----------------core0
3------------------------------------00000011-----------------core0,1
7------------------------------------00000111-----------------core0,1,2
15----------------------------------00001111-----------------core0,1,2,3
31----------------------------------00011111-----------------core0,1,2,3,4
63----------------------------------00111111-----------------core0,1,2,3,4,5
127---------------------------------01111111-----------------core0,1,2,3,4,5,6
255---------------------------------11111111-----------------core0,1,2,3,4,5,6,7





For instance if you wanted to use all six cores, you would enter AffinityMask= 63 in binary that is 111111 (six ones) . However as of service pack 2 FSX IS multi core aware, and assigning an affinity mask of all your hardware cores, will do nothing.

What the affinity mask setting IS good for is telling FSX WHICH cores to use. As I said earlier, the fiber frame scheduling is BOUND to core 0. Since fibers is one of the heavy hitters in FSX, why not isolate it from everything else? For instance to assign five cores, you would enter AffinityMask=62 leaving Core 0 alone with the fiber scheduling.

Also, to avoid thread collisions, turn off hyperthreading, as FSX does NOT support it.

EDIT:
Here is how it works:

Code:
1st(Core0)=1
2nd(Core1)=2
3rd(Core2)=4
4th(Core3)=8
5th(Core4)=16
6th(Core5)=32
7th(Core6)=64
8th(Core7)=128

Keep in mind, that core 1 is refered to as "core 0" core 2 as "core 1 and so on, as far as the OS goes. Now here is how you calculate your Affinity mask. for example:

You want to use 5 out of six cores, but want the first core (core 0) free. look at the corresponding values for each core you want utilised, and add them up. 2 + 4 + 8 + 16 +32 = 62. So in your case Matt your entry would be like so:

[JOBSCHEDULER]
AffinityMask=62 In Binary that would be 111110, but you would read the binary from RIGHT to LEFT. The last zero at the end of the binary represents the "off" or free state of the first core (core 0)

FSX will still use all six, but core 0 will only run the fibers, thus having a "more" so-to-speak equal load across your physical cores.

Now, BE CAREFUL with the math here- some people can get confused. If you had an 8 core processor(which does not exist on the market yet) and wanted to free up the first core (core 0) the AffinityMask would be 254.
A six core would be=62 with core 0 free
A four core would be=14 with core 0 free
A dual core would be=2 with core 0 free

Now, assuming you want ALL cores on FSX straightforward (virtual cores notwithstanding):

8 core CPU= 255 Affinity value
6 core CPU= 63 Affinity value
4 core CPU= 15 Affinity value
2 core CPU= 3 Affinity value

I only post the above ALL CORE Affinity as an example to give a better understanding of the math. FSX will use all cores by default, so setting those affinities will make no difference.


You can of course experiment with different core combos to see what works best for you. I hope you find this helpful.

[vyper883]

@ AK MONGO

http://www.venetubo.com/fsx.html

That is Jesus Altuve's tweaker. How well it works for you, will depend how old your machine is. Newer PC's with multiple cores, and videocards with 2GB will benefit the most. YMMV. If you want to try it, make a backup of your fsx.cfg first, in case you want to revert.

There is a link at the bottom of that page for the shader 3 mod. Give it a try. An ATI card will benefit more than an Nvidia car will. I have an nvidia card and I like the subtle improvement in the fog effects, and water reflections are a nice touch. The only thing you may not like is zooming out of top down view, as the more you zoom out, the hazier it becomes. Give it a try though you might like it, if not, there is an uninstaller tool, ans is completely reversible.

Also the shader 3 tool has it's own entry in your program files start menu. There is an option there, to flush the shader cache. You can use this every time you make changes to your fsx.cfg and FSX will rebuild your shader cache on the next start up. You can read more details about it on that page and link.

Jesus Altuve is actually a pretty knowledgeable fellow. He's earned a lot of respect over at that Avsim forums because of his tweaks. He has added commands to the fsx.cfg file that no one knew could exist there along with some fsx bug fixes.

Nick N of flight1 software is also a respected and knowledgeable individual when it comes to FSX, and his OS tweaks are bar-none when it comes to preparing an OS for fsx use. He is also very good at no-nonsense fsx cfg edits, as well as being a sotware developer himself for flight 1. He is responsible for UTX GEX ect.

These two individuals do not always see eye to eye - Nick is more of a conservative no-nonsense type, whereas Jesus (hey-sus) tweaks are a little more radical, but both of them have contributed immensly in helping the SIM community to understand the inner workings, and shortcomings of FSX, and how to overcome them.

Shader 3 mod. Make sure you look at the readme file. Courtesy of Jesus Altuve aka bojote :

http://www.venetubo.com/sha3mod.zip

[vyper883]

Please delete -extra post

[vyper883]

No. 16 is binary 10000 which means you are only using core 0 (which you can't stop) and core 4. To use the 5 other cores the binary is 111110, or hex 3E, or decimal 62. Each bit in the binary enables a core.

This assumes you have hyperthreading off in the BIOS. Otherwise there are 12 bits with every other bit being a pseudo-core.

Pete

Not to question you Peter, but wouldn't 16 be the fifth core. To assign an AffinityMask to the first core (core 0) the value would be =1. The binary for 16 is in fact 10000 but it's supposed to be read from right to left as is ths example:

http://msdn.microsoft.com/en-us/library/ms187104.aspx

Scroll to the middle of the page where it says:

"As an example of setting the affinity mask option, if processors 1, 2, and 5 are selected as available with bits 1, 2, and 5 set to 1 and bits 0, 3, 4, 6, and 7 set to 0, a hexadecimal value of 0x26 or the decimal equivalent of 38 is specified. Number the bits from right to left. The affinity mask option starts counting processors from 0 to 31, so that in the following example the counter 1 represents the second processor on the server."

[kiek]

As far as I am aware, FSX only uses extra threads for texture pre-loading; all of the work to draw the screen including all windows, AI traffic, autogen etc is done on a single thread. I stand to be corrected, of course, but this is based on my reading of the information surrounding SP2.

In my opinion, neilh is right.
FSX runs 100% of the time at 1 core and uses just one other core incidentally. So a high frequency duel core is better for FSX then a lower frequency quad core or hex core....

Nico Kaan

[Neil Hewitt]

I've been having a browse through the threads at FDS that vyper883 started and I have to say I'm impressed by exactly how deep into the software some people have gotten, and the level of tweakage that is possible. One of the problems with all the new gear is that as standards move on, OS innards change, and so something which you might think would make a big difference might not, and vice versa. For example, Vista and now Windows 7 have a fundamentally different display driver model to Windows XP, and FSX can respond very differently depending on the OS and driver. People don't realise how much the driver quality influences performance. A bad driver on super-fast hardware will slow things down tremendously. With FSX having been unpatched for a while now, there's been no work to optimise it to run with the newer architectures. So it's not a case of just throwing hardware at it and expecting that to work.

While I've taken it at face value that FSX is CPU-bound and not GPU-bound, and that any old modern-ish GPU will deliver impressive framerates, people like vyper883 have shown that you can get a major boost out of newer graphics cards not necessarily because FSX needs more shaders or GPU, but because the interaction between the newer hardware and the drivers and the new OSes is much more favourable to FSX than other combinations would be.

It'll be interesting when the hardcore tweakers get around to building systems based on Sandy Bridge. Any volunteers?

[Peter Dowson]

Not to question you Peter, but wouldn't 16 be the fifth core.

Yes, as I said. Please read it again, I said:

... you are only using core 0 (which you can't stop) and core 4.

Core 4 IS the "5th core". Even you agree that the first one is "core 0", so obviously the 5th is core 4.

The binary for 16 is in fact 10000 but it's supposed to be read from right to left

I don't know why you need to worry about "direction of reading". It is just bit significance. Bit 0 is 2^0 = 1, whilst bit 4 = 2^4 = 16. In other words normal binary bit significance.

Regards
Pete