Archived

This topic is now archived and is closed to further replies.

RENESIS

Which component causes the perf bottleneck?

Recommended Posts

So after several months of no FSX (I said FSX!) I have reinstalled it on the 120gb SSD. The machine is W7 x64 with a GTX460 and 4GB ram. It is an i5 able to run at 4.6ghz. Tweaks-wise I run texture max loader and and external FPS limiter set at 30. By and large it seems very stable and an adequate performer.

 

I am a layperson but interested nevertheless in seeing which hardware component will max out first. I know that FSX performance is largely a question of CPU speed but I was interested to see what was causing a drop in FPS to around 8. It was clearly to do with REX weather generating some angry looking clouds but when changing a view to one which doesn't involve looking at the sky (internal for example) the FPS shot back up.

 

No here's my question: would opening task manager to view performance reveal anything? I did that and could see Memory at about 2.8 ish and CPU at 50-60% spiking occasionally. Therefore I think that maybe the graphics card is the limiting factor. Would anyone agree or is this a flawed test?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

FS will never use 100% CPU all the time. It's a limit within the FS engine itself, it's not properly optimized to use a quad-core CPU to 100%. It will use the first available core up to 100%, but the remaining cores only sporadically.

 

I initially kept my GTX 460 1GB when I built my current system (i7 4770K @ 4.5 GHz). I later replaced it with a GTX 670 2GB. There was no difference at all with flight sim.

Share this post


Link to post
Share on other sites

With my system and flying FSX over dense urban areas and several cumulus cloud layers, my CPU cores will very often reach 97-99%. Very seldom as low as 50%. Having a GTX780 will NOT throttle my CPU in FSX. An OC at 4.6GHz is pretty fast. Get yourself a GTX770 or a GTX680 and you'll sure will have better FSX experience.

Share this post


Link to post
Share on other sites

Upgrade that 4GB of ram to 16GB. When I upgraded from 8GB to 16GB I could not believe the performance increase. My Rig: i7, 580GTX, 16GB ram, vraptor HDD, 1920X1080 display. Most bang for buck I ever spent on FSX.

Matt

Share this post


Link to post
Share on other sites

Thanks for the reply guys, it's much appreciated. Will try an upgrade this coming week and report back. :wink:

Share this post


Link to post
Share on other sites

Upgrade that 4GB of ram to 16GB. When I upgraded from 8GB to 16GB I could not believe the performance increase. My Rig: i7, 580GTX, 16GB ram, vraptor HDD, 1920X1080 display. Most bang for buck I ever spent on FSX.

Matt

Really? What kind of performance increase are we talking about. Just remember that FSX is a 32bit app and hence can't use more than 4GB of RAM. Windows would be able to use the extra 8GB you got for caching, but I strongly disbelieve that having 12GB instead of 4GB extra RAM of top of what FSX can ever use would make any impact at all.

Share this post


Link to post
Share on other sites

I'm not sure exactly where the significant performance increase came from after I added another 8GB of ram, but it was very apparent. At the time of the upgrade ram was quite cheap so I decided to try it since I felt my computer's hardware was about maxed. Running FSX, weather program, ai traffic, high detail add on scenery, and using complex add on aircraft the improvement was noticeable in just about all phases of flight and ground taxiing. Some part/parts of my system are benefiting from the extra ram; I wish I had tried adding more ram sooner. Places and situations where I once had micro stutters are now very smooth. Large complex payware airports I will admit still see a large frame drop but not as bad. I was shocked at how large a difference it made to my sim. The reason I had never tried upgrading sooner was that I believed as you, that the extra ram would be a waste. I can't guarantee that you adding extra ram to your build will result in the same performance benefits, but I swear it was the best under $100 upgrade I have ever made to my rig. In fact if I had known the improvement it would make I would easily have given several extra $100's. Oh, and this improved performance was not seen after a fresh install or defrag; I just plugged it in for 4 4GB modules and started it back up. Totally new sim experience it was.

Matt

Share this post


Link to post
Share on other sites

According to NickN's bible:

 

"FSX does not need more than 6GB - 8GB of physical memory! Be aware, adding more memory is not going to net you any better performance and if you do add more you may find that memory will run higher latency or could be unstable in a high CPU clock situation. Users who may need more memory than 8GB for engineering or A/V production work or 64bit applications, that is understandable but anyone who does not use their systems for much more than FSX would be foolish to purchase more than 8GB. Your version of Windows must support the amount of memory you intend to use as well. Windows 7 Home x64 is restricted to 8GB max."

 

I can't support or refute this statement as I only have 8GB - never tried 16. ...Just the messenger.

Share this post


Link to post
Share on other sites

Regarding the extra RAM... This is a viewpoint from the server side of the house.

 

General recommendation for an 8-core E5-2600 class processor (Intel just today announced 12-core units today - I wuz there) with four memory channels, is to put one DIMM in each channel for a total of four DIMM. Unbalanced memory will subtract from performance. Worst-case put all DIMM on one channel is a 50-percent loss of performance (depending upon application, natch). A single DIMM in each channel will run best. Adding another DIMM to each channel "used to" degrade memory performance by about 10-percent - that is no longer the case with firmware changes. Adding a third DIMM per channel will definitely lower the memory clock speed - the electrical load becomes too high to maintain top speed. It becomes a trade-off of capacity versus capability adding more DIMM units.

 

What Matt may have done is initially placed both DIMM on a single channel i.e., populating slots 0 and 1 (AKA 1 and 2), where it should have been 0 and 2. Adding the new DIMM units added a new memory channel and performance increased dramatically. If Matt cares to experiment, remove DIMM units 2 and 4 (or 1 and 3 - don't make a difference electrically) and see it that extra 10-percent appears.

 

That's what would happen on the server side of of the house... :)

Share this post


Link to post
Share on other sites

I pretty much concur with what most others have said here.

 

Upgrade RAM to 8GB.

 

If your running a Sandybridge 2500K then go for a 2133Mhz kit, if on a 3570K or 4670K go for 2133Mhz or up. In both cases try to get a kit with the lowest CAS latency possible.

 

As far as what you saw with the clouds causing a drop in FPS. The video card will make a big difference here. You'll still see a drop in FPS but not as dramatic. Depending on budget I would recommend an upgrade to a GTX 680/770 or a GTX 780 if budget allows.

 

Cheers!

Share this post


Link to post
Share on other sites

 

 


It was clearly to do with REX weather generating some angry looking clouds

 

Out of curiosity, what AA settings are you using in Nividia Inspector? Flying through clouds with a high Anti Aliasing setting will bring a mid-level GPU to it's knees, significantly impacting your FPS. I had 8xSGSS (IIRC) on a GTX660 and a screen full of clouds would bring my FPS down to the mid teens. I dropped down to 4XSGSS to keep the GPU from maxing out in bad weather.

Share this post


Link to post
Share on other sites

 

 


Windows 7 Home x64 is restricted to 8GB max

 

Home Premium, which is what most have, is limited to 16GB, not 8GB

Share this post


Link to post
Share on other sites

Out of curiosity, what AA settings are you using in Nividia Inspector? Flying through clouds with a high Anti Aliasing setting will bring a mid-level GPU to it's knees, significantly impacting your FPS. I had 8xSGSS (IIRC) on a GTX660 and a screen full of clouds would bring my FPS down to the mid teens. I dropped down to 4XSGSS to keep the GPU from maxing out in bad weather.

 

Hi. Thanks, will try this. Current settings are:

 

 

Antialiasing_zps6c1ae3df.jpg

 

 

 

And screenshot (Note: FPS in this instance was 14.1. Clearing the weather saw FPS shoot back up to 30.):

 

FSXPerformance_zps4a04f925.jpg

Share this post


Link to post
Share on other sites

Yep, 2xSGSS is a no go for a GTX460. No sparse grid transparency supersampling in bad weather if you want acceptable performance.

 

I would also not run 8xSQ coupled with SGSS. 8xS runs better multisampling while SGSS does the supersampling.

Share this post


Link to post
Share on other sites

 

 


And screenshot (Note: FPS in this instance was 14.1. Clearing the weather saw FPS shoot back up to 30.):


Looking at that screenshot, I can tell you that it's not your CPU or RAM that is holding you back there. I take it you don't have an Affinitymask entry in the cfg or use 15. In that case, as long as Core#0 isn't running close to 100% its something else holding you back. In this case I strongly suspect your GPU. I also wouldn't use an external limiter. I'd set the internal limiter to 30FPS and lower the FFTF down to the 0.10-0.20 range.

Share this post


Link to post
Share on other sites

 

 


I later replaced it with a GTX 670 2GB. There was no difference at all with flight sim.

 

Curious.  This runs counter to Nick's insistence otherwise with bottklenecks needing to match CPU to GPU.  Personally, as a long time pc builder/modder, I dont buy his argument.


 

 


Upgrade that 4GB of ram to 16GB. When I upgraded from 8GB to 16GB I could not believe the performance increase. My Rig: i7, 580GTX, 16GB ram, vraptor HDD, 1920X1080 display. Most bang for buck I ever spent on FSX.

 

I find this most unlikely given FSX's 32 bit limitations.

Share this post


Link to post
Share on other sites

I get excellent performance from my 660 ti (voltage mod 1300 OC, ram 760) running with a 4.5Ghz 4770k at 1920x1080.  The ONLY thing that throttles performance in my FSX setup is heavy cloud cover. I would be most grateful to see a gtx 780 or Titan owner flatly prove that their GPU can overcome this difficulty in FSX.

Share this post


Link to post
Share on other sites

Thanks for that link.  Encouraging results performance wise, but still not what I would consider perfect considering the expense, even for a 780. If there was only a way to limit the scope of AA for cloud rendering; that would be a huge performance increase.

Share this post


Link to post
Share on other sites

Sadly that's about as good as it's going to get for FSX unless something radical happens with hardware. Modern games will benefit enormously from the 780 but the way FSX was designed it just cannot benefit to the same degree.

Share this post


Link to post
Share on other sites

An interesting thread.  I am in the process of acquiring the hardware for a new build, so far have  i74770K, HAFX, ASUS Maximus VI Hero, win764 Ultimate and a Gigabyte factory OC 770.  Then I came across NickN's "Bible" and to my dismay he comes down strongly on the side of the 780 when paired with the i74770K. According to Nick:

 

"...if you are building new and you want what this processor and system has to offer then do not neuter the Haswell and go with the GTX780 at any CPU speed.s is the first  intel processor that does not bottleneck the with highest end video card on the market running with a lower CPU speed and the 780 is the best card for this processor."

 

Unfortunately my supplier doesn't do "change of mind" returns so what do i do?  Just go with the 770 and see what happens or sell the 770, take a 100-150 AUD hit and shell out another 800 plus AUD on a 780. What in game difference will a 780 it make over a 770? 

 

Bruceb

Share this post


Link to post
Share on other sites

Unfortunately my supplier doesn't do "change of mind" returns so what do i do?

 

Which supplier did you purchase from? Have you opened the box/used it at all?

 

Where abouts in Australia are you?

 

As far as difference in FSX, the main things the 780 will do noticably better is AA, particularly in bad weather etc.

Share this post


Link to post
Share on other sites

An interesting thread.  I am in the process of acquiring the hardware for a new build, so far have  i74770K, HAFX, ASUS Maximus VI Hero, win764 Ultimate and a Gigabyte factory OC 770.  Then I came across NickN's "Bible" and to my dismay he comes down strongly on the side of the 780 when paired with the i74770K. According to Nick:

 

"...if you are building new and you want what this processor and system has to offer then do not neuter the Haswell and go with the GTX780 at any CPU speed.s is the first  intel processor that does not bottleneck the with highest end video card on the market running with a lower CPU speed and the 780 is the best card for this processor."

 

Unfortunately my supplier doesn't do "change of mind" returns so what do i do?  Just go with the 770 and see what happens or sell the 770, take a 100-150 AUD hit and shell out another 800 plus AUD on a 780. What in game difference will a 780 it make over a 770? 

 

Bruceb

 

Funny cause he was recommending that 770 to everyone to couple with Haswell, while bashing the 680. When I pointed out to him the 770 was just a reworked 680 for the most part, he deleted my posts, banned me from the forums and started with all that 780 + Haswell thing.

 

Just get the 770 and ignore Nick the revelator, seriuosly. Haswell is just a 10% faster than Ivy Bridge (which also supports PCIe 3.0 if that matters to you, and it shouldn't) and a 15% faster than Sandy Bridge, so it bottlenecks just the same in FSX typical CPU limited scenarios

Share this post


Link to post
Share on other sites