Nvidia SLI Issue

[steelzor 10]

Hi,

I am having trouble getting SLI to work with ARMA2 and ARMA2:CO. I have tried out my system in 3DMark11 to test whether the SLI is correctly enabled and working and it definately is. I am running the latest version of ARMA2 and the latest drivers for nvidia as I only built the system two days ago.

My system is as follows:

Core i7 2600K @ 4.3GHz

8GB DDR3-1600MHz RAM

Intel G2 80GB SSD

nvidia GTX570 SLI

Running all on Windows 7 64-bit. I haven't changed anything in the config files but I did max out the settings inside ARMA2. I have tried altering the settings inside the nvidia panel to force alternate frame rendering 1 which resulted in 20 fps in the standard benchmark rather than 80.

When testing with single or SLI, it was always around high 70's, and using Afterburner shows either 1 card at 90% if SLI disabled, or two at around 40-50% if both enabled.

I believe that SLI is not correctly being used and only 1 card is being properly run. Does anyone have any ideas how I could get this working? I will say that you cannot suggest it is my CPU/HDD sub-systems holding me back as you cannot get any better at this stage and the fact that the numbers are basically identical between SLI disabled and not, shows this.

Edit: I forgot to mention that it is the Steam version of the game though doubt this is a problem.

---------- Post added at 11:14 AM ---------- Previous post was at 11:08 AM ----------

Alternate Frame Rendering 2 seems to set it back to full speed pretending its using 2 GPU's when it uses one.

Edited June 18, 2011 by steelzor

[CameronMcDonald 146]

I have an SLI set of older cards, 285s. SLI works - just not very well.

[steelzor 10]

Did you have to do anything to get them rolling at all? I mean I would have expected *some* difference at least but I'll do a full runthrough and compare the two and see the numbers.

[CameronMcDonald 146]

Hmmm. Not particularly, latest drivers or thereabout, naturally - basically, I've just got my SLI settings on the CP for A2 to auto-select (which turns into "custom" for some reason).

I suppose the comfort you can take away from this is that your rig will probably handle A3 quite respectably, even if A2 runs comparatively shittily. The 285s were in that boat for A2.

[steelzor 10]

Naturally its runs pretty smooth at the highest settings bar view distance :)

But I didn't spend so many $$$ to get 'pretty smooth'. I expected bloody flatout mindblowing.

[Leon86 13]

Sli is working fine, the problem is arma is mostly cpu limited. You can adapt settings to load up the gpu's more or just create a gpu limited situation ingame. Throw a couple of smoke grenades and zoom in on the smoke, that'll load up the gpu's.

[steelzor 10]

Seeing as I wasn't maxxing out my CPU in the benchmark seems unlikely its CPU limited....

[Leon86 13]

well it is.

Not showing 100% load on the cpu doesnt mean the program is not cpu limited. Even if it doesn't even max out one core, sometimes the main thread has to wait for information from another thread on another core. The other core doesnt show 100% as well because it's an average over time.

If you see one of your cores regularly over 80% you're probably cpu limited allready.

If you want to put your system to work when playing arma you'll have to take the time to adapt settings to suit your system.

[pendragonuk 0]

Have a look through this thread LINK What you are describing is almost exactly what is happening to us ATI CrossfireX users. You think your ticked off this guys has a pair of ATI 6990! 4GPU's and still no improvement to frame rate. You would think my pair of mid price 6870's do something to help, but no.

ArmA:2 doesn't use multiple GPU's to improver frame rate. It just shares the workload across them but nothing happens faster than with just having the one.

On my system Core0 runs at around 90% Core3 runs at around 30% the other four cores are doing little or nothing bumping along the bottom of the graph.

There are a great many factors but it boils down to the game not making proper use of your hardware. It is supposed to be multiprocessor (SMP) but still favours one/two CPU's, it has a limit to the amount of RAM it will use even where there is more for it. It makes no use of multi GPU systems. To all intents and purposes ArmA:2 is a dual core game.

note: Please don't take this as me having a downer on the game, I love it. However I have a new and unintended hobby, ArmA tuning. This is where I spend hours reading forums and testing out different things.

[Leon86 13]

Arma scales near perfect to 3 cpu cores. 3->4 and you can still notice an improvement.

Multigpu works fine as well, I run 2 gtx260's in sli and it runs well. In the bench scenario's I get a decent gain, it's most noticable in gpu heavy situations, like blowing something up with a littlebird. lots of smoke on screen loads up my gpu's to 100% easily.

And it's not bohemia's fault if multigpu doesnt work, that's ati and nvidia's job.

An easy way to load up the gpu is to reduce the cpu intensive settings like viewdistance model detail and terrain detail. Also make sure shadows are on high or very high, as medium or low shadows are done by the cpu and high/very high are done by the gpu.

[steelzor 10]

Thanks for the tips. It's just mildly annoying have people suggest its a CPU issue when I am running an i7 2600K at 4.5GHz. You don't get much faster than that. I've tested out all my other games and they engage the SLi correctly(only 5 at this stage due to reinstall).

Because of all the BI fanboys filling these threads with FUD blaming the users, it prevents the core issue perhaps being fixed. Even if it were CPU bound there would be some change in FPS.I am in the same boat as Pendragon. I love ARMAII but I want it to use my full hardware available.

Crossing my fingers that its better for ARMA3.

---------- Post added at 02:01 AM ---------- Previous post was at 01:32 AM ----------

Okay Ive finally gotten SLI working. No idea how.

But I have this weird white/grey flickering that was mentioned in another thread. It dolesnt happen too much on the ground but in a jet its almost constant. Do we have a fix for that?

[Leon86 13]

well the "problem" is that bis allows you to put the viewdistance slider on rediculous levels, cpu limiting everything no matter how overclocked you are, although on small islands like utes you can easily do that. but you can also put the 3d res on 200%, that'll get the gpu's working.

Not sure about the flickering. I dont have that I think. The only issue I have is the preview loading screen in the editor going white-black-white-black, very annoying.

[Rich_R 1087]

I have a very similar set up to the OP and have my 570's in SLI. When you open up your nvidia contol panel, do you have the cards set to SLI? If yes, as mentioned in earlier posts, you are actually seeing the gain.

I had run some benchmarks after updating some Nvidia drivers and noticed the performance was off by about 10-15 fps. Checked the SLI, it had been reset to single (or essentially no SLI). Corrected it and I was back to my better performance.

There are some helpful tips in the 'Nvidia cards users read here' thread, and you have to patiently sift through two years worth of psots to get the info (I worked backwards), they'll help you perfect your contol panel for the different settings.

Personally I like eye candy and have all my stuff on very high, consequently dont enjoy the 70's or 90's FPS some people boast on here.

[bangtail 0]

People here blame the users because 80% of the time it is guys running vhigh w/10K VD and wondering why they aren't getting 120FPS.

It is a CPU issue no matter how much you choose to believe that it isn't. It's not that your CPU is bad or not functioning correctly, it's that the game is very CPU intensive due to AI routines etc.

Other games simply don't have this restriction which is why you don't experience the same problems elsewhere.

SLI works perfectly in ArmA 2, the only real exception is in cities where the combination of complex geometry and AI routines will also limit the CPU.

Getting the game running correctly on any given rig is a excercise in playing with the settings until you get it 'just right'.

Good luck :)

Edited June 19, 2011 by BangTail

[Rich_R 1087]

.....Because of all the BI fanboys filling these threads with FUD blaming the users, it prevents the core issue perhaps being fixed.

Not to go off topic, but I would hardly call the BI players fan boys. Actually consider them demanding and discriminating gamers. This can be as much of a challenge to BI as well as new players posting on these forums.

The challenge is, new players will ask a question or start a thread without reading through the existing threads where the topic has been discussed quite thoroughly, or just come and complain about the hardware demands of the game, which are also thoroughly discussed.

From what I understand, the core issue is the nature of the game, being an open sandbox with everything happening around the player whether they necessarily see it or not. The engine still takes cpu power to calculate and implement everything.

As Bangtail points out, Arma 2 is not the game to max everything out and then get upset that you're not in triple digits on the FPS. My rig is similar to yours and my computer can run nearly every other game out there with all the eye candy and not even break a sweat. However, I've had to play with the setting to find that middle ground of looking good and an acceptable performance that I can enjoy.

We would all be lying if we told you this determination isn't an ongoing matter with Arma 2:)

[pendragonuk 0]

Some times I feel that BIS could have saved a lot of trouble by just having two settings, Low and Normal :) I have come to learn that in this game Normal = normal!!! I love reading the posts from guys with single core and 2Gb or RAM and a 6 year old G/Card. They run the game without complaint in part because there expectation is spot on. It's muppets like me that at first were expecting eye candy... I must remember to turn off FRAPS so that way I don't know what is going on ;)

Edited June 21, 2011 by PendragonUK

[liquidpinky 11]

It isn't just CPU bound, it is also down to GPU. I can run far higher draw distances over three monitors than I could over one with my exact same setup but only the GFX cards were different. Previously I ran SLi GTX285s and now run GTX 580s, the extra memory on the 580s is put to use as well.

In a lot of the cases the person does tend to try an put that slider waaaaaaaaaaaaay to far to the left for their own good though.

In all seriousness, the game looks best on between 4.5 and 5k draw distance to keep the fogging looking more natural. When you go above the fog starts to look more defined and stands out like a sore thumb.

I have done tests on up to 100k draw distance on some maps, not Chernarus obviously as I don't like the smell of my PC components being on fire, and have found this to be the case.