Is SLI a good way of getting increased frame rates in FSX?

[Paul G]

Hey y'all

I haven't seen much mention of using SLI to tie two identical video cards together to increase graphic performance. Anyone have any experience of this or opinions?

Thank you

Paul G

[Padraig]

Hey y'all

I haven't seen much mention of using SLI to tie two identical video cards together to increase graphic performance. Anyone have any experience of this or opinions?

Thank you

Paul G

When I built my last rig I bought two 8800 GTX OC2`s when they came out, Ran them in SLi, and low and behold it did nothing for FSX, FSX does not support SLi. FSX is CPU dependant more or so. If your thinking about Sli for FSX then I would recommend you spend money on a better CPU.

This has also been mentioned on the FSX developers site too. Also some of the guys here also had their input on the matter when it came up before.

[Trevor Hale]

Biggest problem Paul, is 100% For sure FS9 will not utilize the second processor, so no point really!

[Paul G]

Yeah that's kind of what I was expecting to hear. It's a huge investment if it don't do nothin'.

I hear what you're saying about higher speed processors. But will, for example, a quad core processor have any impact compared with dual core? This is not such a dent to the wallet

Thanks

[Padraig]

Yeah that's kind of what I was expecting to hear. It's a huge investment if it don't do nothin'.

I hear what you're saying about higher speed processors. But will, for example, a quad core processor have any impact compared with dual core? This is not such a dent to the wallet

Thanks

Yes a Quad is good. I first started with a 2 core duo 2.4ghz which was nice, I then overclocked it to 3.8ghz which was good until I could afford the Quad. Bought the quad and now I don't need to OC the Quad for a while. So a quad core worked wonders for me compared to the Overclocked 2 Core Duo. I actually sold one of the cards to help with the price of the Quad core. There are articles about CPU usage and mapping on the FS Developers blog site too which will help guide you, Also Low latency memory would not be a bad idea along with a decent graphics card too + the quad core. You dont want bottle necks!

[Prof Bill]

Hi Padraig,
You attracted my interest on your overclocking figure for your dual core.
I wonder would it be possible to ask what type of processor (model), motherboard and was it an overclocking toolset provided by the motherboard manufacturer such as AZUS.
I have a few dualcores with efficient coolers and motherboards etc. here that might be suitable and would like to challenge some youngsters with an overclocking project that was achievable in terms of demonstrable results.

Any advice or input would be most welcome!

Bill.

[Padraig]

Hi Padraig,
You attracted my interest on your overclocking figure for your dual core.
I wonder would it be possible to ask what type of processor (model), motherboard and was it an overclocking toolset provided by the motherboard manufacturer such as AZUS.
I have a few dualcores with efficient coolers and motherboards etc. here that might be suitable and would like to challenge some youngsters with an overclocking project that was achievable in terms of demonstrable results.

Any advice or input would be most welcome!

Bill.

Hi Bill, yes of course I don't mind giving some more details on my setup on which I achieved. Heres a list of the hardware I used.

CPU = 6600 model (They are going pretty cheap now)
========================================
Motherboard = Abit IN9 32-Max

http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=509279&source=ciao

========================================

Memory used: OCZ DDR2 PC2-7200 Special Ops Edition 4GB

========================================

All overclocking was done through the BIOS (Using the Guru Software is not recommended) As regarding the cooling, I'm using a pretty serious watercooling system in this machine that I custom built from good parts and using heater cores for the radiators. I can turn up the Vcore of the chip to 1.6 volts plus without having to worry about temps hence why I was able to get the processor to run at such a high cycle rate. If your using the stock cooling you will be able to run that chip at about 3.2ghz on stock volts without any hassles. Just make sure you keep an eye on the temps.

Basically the process I had to do to achieve the clocks is overclock the memory, Northbridge, CPU unlinked, and find the sweet spot. Also increasing the voltage to different areas on the motherboard is essential to keep the clock running stable but increases the temps as your well aware of.

The software I used to help me in the process of monitoring and stress testing the overclocking was,

Cpuz , Prime95, Core Temp. (All are free Applications)

I hope this answers your questions a little, if your unclear on something I have written then please do not hesitate to ask.

[Hardlight]

Paul,

SLI is a function of the graphics driver. It is not the case that FSX 'does not support SLI'. Most peoples performance is however limited by the processor. If your processor can keep the graphics cards busy then you will see increased performance with a SLI configuration. Since SP1 FSX has been able to utilise multiple threads and take advantage of multi cores (mainly texture handling).

Regards,
Will

[AndyT]

SLI is also more of a Driver issue. If you run Vista with DX10 and have the correct SLI drivers, then you will see some gains, but how much is anyones guess.

[Vanoyen]

Hi,
I’m new to the forum so I’ll say a quick hello first. I’ve been a flight sim fan since FS9 and i’m mostly into flying the Boeing 737’s (PMDG’s NGX 737 for FSX has been coming soon for over 12 months now and i’ve given up waiting) and the gliders. Trying to put some money aside to do some real gliding lessons and hopefully get a license.
When FSX was released I was most impressed with the improvements over FS9. I did however get pretty poor frames to start with. I struggled for ages, applying every tweak i could find to FSX and they did help a lil bit but when I disabled SLI, i got a frames boost of about 15 to 20 frames which is massive. I’m now getting good frames (above 30 most times) and it’s because I’m just using one graphics card instead of 2. Strange how software works sometimes.
Anyway, i’m still getting a problem however with the DX10 preview and the AA settings. If I enable AA and run the DX10 preview I get a black screen that only a cold reboot will fix. I read that it’s something to do with the nVidia drivers so hopefully they’ll address the isue with the next release. Untill then, i’m running the sim without DX10 because it looks to crappy without any AA.

[LUFTY]

Paul,

SLI is a function of the graphics driver. It is not the case that FSX 'does not support SLI'. Most peoples performance is however limited by the processor. If your processor can keep the graphics cards busy then you will see increased performance with a SLI configuration. Since SP1 FSX has been able to utilise multiple threads and take advantage of multi cores (mainly texture handling).

Regards,
Will
Hi Will totally agree that the number one bottleneck for FSX is the processor speed and number of cores.

One other point to add is that DX10 offloads some of the processor overhead onto the graphics cards so a faster graphics card and running DX10 can reduce the processor overhead.

I am getting really good results with the ATI HD3870X2 because of this and am anticipating even better results with the soon to be released ATI HD4870X2 which is two HD4870 cards joined together in one card via Crossfire (which is the ATI version of SLI).

The other important bottleneck is the speed of the graphics card bus with PCI Express 2.0 allowing a much bigger throughput than PCI Express 1.1.

With high resolutions and complexity FSX will max out on data being passed over the PCI Express bus.

Kind regards


Lufty

[Denis]

Hi,

FS9 and FSX cannot use multi GPU. They can work on such setup (SLI, Triple SLI or Dual GPU Card). But Each graphic cards benchmark (like these from Toms'hardware) can demonstrate that e.g. a 9800 and a 9800GX2 have same results in FS. This is true for every GPU generation, Nvidia or ATI.

And this is true for every resolution ! you can see this on a 800X600 15" screen or a Triplehead2Go with trhee time 1680X1050 22" widescreens ! Multi GPU has no effect !

The last weeks, we saw that FSX has paradoxal results with hardware, the last Nvidia GTX200 cards are slower then the 2 years old 8800GTX. A month later, new drivers gave same fps, but not better then a 8800GTX. The same GTX200 outperformed very well each other single GPU card in other games. So it is...

If you want invest better, buy a single PCI-Express 2.0 compliant GPU (and motherboard) card and use the saved money with a faster CPU, a good CPU cooler, and overclock your CPU. And then you will feel the difference !

Best regards

Denis

[LUFTY]

Hi,

FS9 and FSX cannot use multi GPU. They can work on such setup (SLI, Triple SLI or Dual GPU Card). But Each graphic cards benchmark (like these from Toms'hardware) can demonstrate that e.g. a 9800 and a 9800GX2 have same results in FS. This is true for every GPU generation, Nvidia or ATI.

And this is true for every resolution ! you can see this on a 800X600 15" screen or a Triplehead2Go with trhee time 1680X1050 22" widescreens ! Multi GPU has no effect !

The last weeks, we saw that FSX has paradoxal results with hardware, the last Nvidia GTX200 cards are slower then the 2 years old 8800GTX. A month later, new drivers gave same fps, but not better then a 8800GTX. The same GTX200 outperformed very well each other single GPU card in other games. So it is...

If you want invest better, buy a single PCI-Express 2.0 compliant GPU (and motherboard) card and use the saved money with a faster CPU, a good CPU cooler, and overclock your CPU. And then you will feel the difference !

Best regards

Denis
Hi Denis

I agree PCIe 2.0 does make a difference to framerates whereas dual cards has little if any affect.

The latest performance benchmarks from Tomshardware highlight this although they used a relatively slow CPU which is by far and away the biggest bottleneck with FSX.

http://www.tomshardware.com/reviews/radeon-geforce-comparison,2007-18.html

Regards


Lufty

[strychninekiss]

Hi all.

Yes, frame rates in FSX is definitely based on the CPU like Denis said!
I currently have a core 2 duo E6850 3.0GHz I get around 8-15 FPS with high settings, I am sure if I clock my CPU up a bit I can manage around 10-20 FPS.

However I have never overclocked a CPU and Im kind of nervous! =)

//William

[AchillesP]

Biggest problem Paul, is 100% For sure FS9 will not utilize the second processor, so no point really!


Hi,

There is a trick to activate all cores for fs9.

1.) run fs9
2.) open the program scheduler and find fs9.exe
3.) right click and properties. Check all procesors.

You have to do this every time you run fs9.

[Padraig]

Hi,

There is a trick to activate all cores for fs9.

1.) run fs9
2.) open the program scheduler and find fs9.exe
3.) right click and properties. Check all procesors.

You have to do this every time you run fs9.

You can create batch file with notepad and use the command for setting the affinity for the fs9.exe.

Launch the Fs9.bat file every time you want to use FS2004, make sure to use the START command at the start of the line so the CMD window will close after the exe is launched.

Google "Batch file set affinity for exe" and you`ll get some examples.

I am not sure if setting the infinity is going to give you better performance tho. Just thought I give you tip without having to do the infinity thing every time you start fs9.exe manually.

[LUFTY]

Hi,

There is a trick to activate all cores for fs9.

1.) run fs9
2.) open the program scheduler and find fs9.exe
3.) right click and properties. Check all procesors.

You have to do this every time you run fs9.
Hi Achilles

This will tell Windows to allow all processors to be used for FS9 however it will not make any performance difference as FS9 is not multithreaded which means in simple terms that the whole application runs as one processing thread. Therefore whenever FS9 wants to do some CPU processing it can only send the requests to the CPU one at a time rather than sending parallel requests to seperate cores.

In fact this is not the best way of optimising FS9. A better way would be to use the affinity option to make say core 0 run all windows tasks etc. and set the affinity of FS9 to the second core.

Regards


Lufty