Is SLI really worth it or am I expecting too much?

[svenpurple7]

Hi there guys.
I have done some upgrading to my PC and I am now using a 6800 Ultra PCI-e.  The improvements were immediate.  I then bought a new payware aircraft (PMDG Beech 1900 C) and I love it except that it appears to be a hog on the graphics card.  It sometimes makes the performance stutter.  I don't get that with any other payware or freeware aircraft.

For what I paid for the 6800 Ultra, I would expect it to handle just about any payware without stuttering.  So the question is: would getting another card and running them SLI help?  By help, I don't mean getting 80 fps in places where I already get 50 fps.  By help, I mean 20 fps where I now get 15 fps.  Please let me know if I am expecting too much out of my graphics card(s).

Thanks in advance for your input,
Ben.

[richardd43]

I have two 6600GTs in my computer but am not running SLI as I have 4 monitors connected. In answer to your question (according to the book) two 6800s in SLI mode should kick butt.

I am not a FPS freak but when I set mine for unlimited I can maintain 75 FPS with most airplanes (non payware).

SLI will drop you to 8 pipes vs 16 but you have two processors working.

Would be interested to know what happens if you go to SLI with the 6800s

[Dan]

I didnt know that it dropped pipes...  ???  :o Would it be possible to unlock the pipes in RivaTuner or such like back up to 16? Think how that would go!
Dan  ;)

[Delta_]

That is not true.  The motherboard changes from 16x PCI-E, that you get for one card, to 8x PCI-E, for two cards.  The reason for this is the lanes for the data transfer in the motherboard will be over-loaded if both cards ran at 16x PCI-E.

[Dan]

So what your are saying is that all 16 pipes are still there, but its gone down in its bandwith type of thing? Like staying at 16 pipes, but going to AGP 6X?

BTW is there any card with more than 16 pipes?
Dan

[Delta_]

The slot bandwidth changes and the pipes stay the same.  However 8x PCI-E is not a noticeable amount slower than 16x PCI-E.

No card currently available has more than 16 pipes, but check out the ATi R520 'Fudo'.  This will have 32-pipes.  Fudo is the chipset and i believe means heart in Japenese.

[Dan]

Well if thats tghe case then its goin on the wish list! Now think of them in SLi! I understand now I think. Thanks Andy.
Dan

[svenpurple7]

I am not a FPS freak but when I set mine for unlimited I can maintain 75 FPS with most airplanes (non payware).

I used to gauge the performance of my sim by fps, then I realized that Shift+z can be your enemy.  IMHO if it looks good and runs smooth, then that's all you really need.

That is not true.  The motherboard changes from 16x PCI-E, that you get for one card, to 8x PCI-E, for two cards.  The reason for this is the lanes for the data transfer in the motherboard will be over-loaded if both cards ran at 16x PCI-E.

My mobo (A8N-SLI Deluxe) manual says the following:  "In Normal mode, only the PCI Express blue slot can be used for PCI Express x16 graphics cards.  The PCI Express black slot functions as a PCI Express x1 slot."
Is that why the pipes go down from 16 to 8?  In order to provide the same number of pipes for both cards?

Anyway, I think that my stuttering issue is because my old ATI drivers are causing problems even though i uninstalled them and ran driver cleaner.  I was going to put together a RAID drive which means a complete re-install of FS9.  That should take care of any old ATI drivers for sure.  If all works out, then I will decide on two 6800s in SLI mode.  Any opinions?

[Delta_]

My mobo (A8N-SLI Deluxe) manual says the following:  "In Normal mode, only the PCI Express blue slot can be used for PCI Express x16 graphics cards.  The PCI Express black slot functions as a PCI Express x1 slot."
Is that why the pipes go down from 16 to 8?  In order to provide the same number of pipes for both cards?

No, the 16x PCI-E bit means that it has 16x the bandwidth of the 1xPCI-E bandwidth.  The pipelines is dependant on the GFX card.  The 16x PCI-E is dependant on the motherboard.  The only reason the motherboard chooses 1x PCI-E for the second slot is that if both sockets operated at 16x PCI-E the motherboard would overload all its bandwidth and crash.  The number x PCI-E simply tells you how much bandwidth is potentially used.

[congo]

It's worth it if you are willing to pay a high price for a relatively small gain.

It's worth it if you must have the very fastest available by a small margin.

It's worth it if you get your graphics cards at a "2 for 1" sale!

FS9 doesn't seem to respond to better hardware as most other apps/games do. The absolute best systems often still struggle with it. I wouldn't be concerned about your current stutter.

Your particular FS9/hardware setup is somewhat unique and comparisons with other systems can be misleading. If one or two payware aircraft are giving you grief..... you are not doing too bad at all.

SLI is clever marketing for a starving public. (Some people seem willing to pay anything for every precious FPS point they can buy!)

I suspect SLI will turn out to be a dud in the end, especially when newer technology enters the market and people find they are stuck with TWO very expensive and out of date cards!

The whole world seems to be struggling with graphics performance. We also pay a high price for the privaledge of what we currently have. I only hope the manufacturers are making enough profit to speed R & D and deliver us something that will make threads like this a thing of the past.

[richardd43]

Hi-D I agree with your correction of what you said about my comment. Was what i meant, I just said it poorly.

[svenpurple7]

No, the 16x PCI-E bit means that it has 16x the bandwidth of the 1xPCI-E bandwidth.  The pipelines is dependant on the GFX card.  The 16x PCI-E is dependant on the motherboard.  The only reason the motherboard chooses 1x PCI-E for the second slot is that if both sockets operated at 16x PCI-E the motherboard would overload all its bandwidth and crash.  The number x PCI-E simply tells you how much bandwidth is potentially used.

You can't teach an old dog new tricks, but you can teach him about PCI-express graphics cards.  Thanks for the lesson.


Congo, you bring up many good points.  I am not interested in total FPS but I am interested in better performance.  I have been puting my sim through a lot and I notice that the performance is what I would consider less than desirable in some spots.  I have come to the conclusion that I am asking too much out of FS9.  Let's see what FS10 brings to the picnic.  Also, somebody has to support the manufacturers so it might as well be me.  ;)

I am going to pick up my new Raptor drive today and I'll see what results I get from that.  I may still get another 6800U and SLI them just so I can see what the result are.  I'll look at it as a learning experience.  If SLI technology tanks, oh well, a learning experience again.  :P

If all else fails to satisfy my desire for performance, maybe I should just turn down my AI traffic  ::)

Any other opinions and constructive criticisms are welcome.

[congo]

There seems to be a misguided line of thought in many PC users interpretation of FPS.

Given any PC/software configuration, Frames Per Second is our only true indicator of graphics performance.

It's useful for fine tuning where the human eye is fallible.
An adjustment here and there, backed up by comparitive FPS testing is solid proof that your settings/hardware changes are having an effect or not.

FPS testing will not work if you can't set up a test scientifically, everything in the PC environment must be identical except for a single change to make a valid comparitive analysis.

I suspect that people's mistrust in FPS testing may be due to a number of factors, but they need to understand it's validity. It is a direct measure of graphics performance under the conditions of the test. There is no magic, nothing unexplained or mysterious.

FPS testing has a direct relationship with overall graphics performance. Any improvement in FPS through tweaking, drivers or hardware changes is usually a good thing unless quality has been sacrificed. (robbing Peter to pay Paul...)

Increasing FPS beyond your ability to see the difference is pointless of course, as are tweaks that make FPS rise at the expense of image quality. (unless of course, FPS is so low that image quality must be sacrificed.)

Unfortunately, and in reality, most of us have to downgrade our image quality through lower resolutions, inadequate filtering, and reduction of detail until we do get an acceptable FPS to properly use and enjoy the software.

This is where FPS is an essential tool for us, because it is a true way to measure changes that we make in our efforts to get a good compromise between speed and quality on our displays.

Somebody's 75 FPS is pretty much meaningless to me unless I have a comparison, such as what their last tested FPS was before whatever change they made.

75 FPS might be attained on their system at quality settings so low that I wouldn't consider using them.

FPS results are mainly useful for two things:
1. Individually, to fine tune our PC's
2. Comparitive testing between hardware types/models

If I haven't explained this well enough let me know, or maybe someone else can add in.

Make FPS your friend!

[svenpurple7]

Well said Congo.  I have pretty much thought of FPS the same way.  I am sure I could get 75 fps all the time but what would be the point if everything would look like "stick figures":P  I guess I didn't make it clear enough that performance to me meant image quality as well.
I don't see the point of reaching some huge number of FPS while flying at 25,000 ft over a desert.  Anyone can do that.  It's the crowded airports that bring my gpu to a grind.  That's where I want to see an improvement.  Even a slight one will do while keeping a good image quality.

Thanks for your comments.  I am always willing to hear what you all have to say.  How else am I going to learn?

[marick626]

The problem can be memory.
Some payware need allot of space... some dont.
if you have allot of aircraft, like I had. The fps can nosedive if you dont have proper memory. That is why my new alienware computer will have 4gb .
Sorry, didnt mean to brag. but yeah. Memory can be a big problem. My Current computer only had 67mb left and the max fps were about 20. And no. I have a good graphics card but not one like the 6800.

If I were you. I would enjoy the framerates even if its 20 or 30. Thats still pretty good.