I was looking forward to the addition of SLI support in 1.019. I tried a GTX 590 briefly but had too much micro-stuttering. Overall FPS were very good, but they fluctuated too much. I don't have any previous SLI experience and didn't have time to delve too much into the more obscure SLI settings, though, so I wonder if I missed something.

So are others using SLI? How well is it working? Any special settings?

Also, any sense whether SLI or Crossfire works better? I've seen some folks using ATI cards who seem to be running Crossfire.

Thanks.

Queeg,

SLI works, but read my comments in the Graphics Primer here.

http://riseofflight.com/Forum/viewtopic.php?t=20189

Jason

Crossfire works but I get large patches of untextured landscape. The only fix for me is to restart and hence reload every single mission, or to turn off Crossfire. Obviously I don't want to turn off Crossfire because when it works it is great. For some reason the problem doesn't manifest itself in MP.

I think the loading routine is the cause of the problem, it simply doesn't load all of the textures first time when Crossfire is enabled.

Higher spec cards yield poorer results from SLI.
My 480 sli didn't show any improvement on FPS using standard settings.
However it did improve with super sampling selected.

But even with sli on and super sampling on the fps was not good enough to leave on. So I'm back to using a single card.

Caveat: Lower spec sli set ups were reportedly yielding better results

I have an AMD 5970 whch is a single "card" with two GPU's in it. I don't see any difference between using and not using Crossfire. I'm not getting any anomolies when using Crossfire ( I just upgraded to Win 7 64 bit) and I guess that my machine runs fast enough with a single 5970 GPU and a 3.5 gig i7 quad cpu and 12 gig of ram.

I have everything cranked to max except for anti-aliasing which is set to X4 instead of X8 and I'm showing 39% memory usage.

ROF doesn't have anything built in to measure fps-correct? I guess I need to install FRAPS to see if there's a difference...

Thanks, Jason. i read your primer before the update and knew micro-stutters were a possibility. Not a surprise, because I know it's a common SLI problem. I mainly was wondering what others are experiencing and if some settings work better than others.

Oh Cr@p, I forgot about that!!!!!!!!!!!! I had to turn Crossfire OFF because I was getting microstutters!!!!!!!!!!

Sorry-too many adult beverages last night-some buds stopped by and one was carrying some Patron

I've found with using 6000 series ATI, Alt-Tabing gets rid of the untextured landscape

It took me most of the weekend to get crossfire to work again after the last patch. I did not see micro stutters so mebbe that is an SLI thing but with crossfire I got the strobe lighting bad.

Runs OK in crossfire mode.

SLI actually worked fine for me before the 1.19 patch, but now I get all kinds of graphical problems with it enabled. Using nvidia 560 ti 2gb cards.

SLi wasn't actually implimented before this patch. Dual cards and single cards yeilded identical results. While you may have had Sli selected you would actually have gained anything over a single card except extra power drain and heat.

Thank you, you have saved me a lot of long reloading, the Alt-Tab method fixed the problem instantly. I would lo0ve to see a fix by 777 but this is better than my method.

I have said it before, and I'll say it again: SLI must be the single most misunderstood subject, among PC discussions, of all time...

There is no requirement for an application to "support" SLI for you to benefit from it.

I still don't get what all the fuss is here within RoF about this new "support" for SLI. It's true an application can be written/configured/optimized to work better with SLI, perhaps (get more benefit, or get benefit without manual profiles or adjustments).

But it is not true that a game has to support SLI for it to work. In fact, certain SLI modes are intended specifically to benefit games that do not have SLI "support" built in.

And, in this case, it seems the effort to "support" SLI has actually caused it to work very poorly, where obviously some people were successfully using it (and benefitting from it) before the "support" was implemented.

Reasonably speaking, all it takes is setting up a profile. Naturally, how much benefit you get and what features you can use will vary by the exact game, your hardware, drivers, etc. But - at least according to Nvidia - there is at least potential that *any* app can benefit from SLI.

But don't take my word (and for God's sake not the word of the thousands of "experts" online who really know nothing about SLI)...

...simply go to the Nvidia website and read for yourself. It's all explained there.

(And to respond, albeit late, to another post on the subject of SLI...having two cards *DOES NOT* double the graphics memory. Some people apparently have more money to throw at their computer, than they have knowledge about what they're spending money on)

Although I don't run SLI currently, I have - with (3) different setups. It works, and works well, within the constraints of what it's designed and intended to do. Personally, my experience has been this business about 'micro-stutter' being blamed on SLI is a load of hooie.

All of the "stutter" I ever experienced was caused by a graphics setup that grossly outclassed the mass media storage subsystem's ability to feed data fast enough (that's your hard drive, for layfolks).

ALL the stuttering-type problems I had disappeared completely when I built the fastest mass media storage subsystem I could possibly afford (4 SSDs in RAID 0, on a genuine 'hardware' controller). And I'm not the only person to experience this, either. I have a metric *ton* of experimentation, testing, and data to support this conclusion.

It's very common to see system specs that go on and on about the greatest CPU, video card, tons of memory...even the power supply and the case a poster has. But what is frequently omitted, or only included as an afterthought is "Oh, yeah...all that stuff above, and I have a hard drive".

Simple fact is the hard drive is still and by far the slowest part of a computer today. And yet they are overlooked like b@stard stepchildren when it comes to all these 'hotrod' systems you see in folks' sig lines.

Why build a ultra-performance gaming rig, just to leave it anchored down by 45+ year-old technology? Why buy all that sporty hardware and ignore the slowest part; and that which handles every byte of data that the entire machine processes, ever?

Anyway, sorry to go off - just that SLI gets blamed for things I think are more often the part of bottlenecks elsewhere in the system, and/or poor implementations. Indirectly, it's on-topic.

Regards,

Ah but a lot of the resources stored on the harddrive are cached into memory (video or system) while the mission loads. So the slowness of a hard drive should not really be a problem during play unless the game is actively loading resources from files on the harddrive during gameplay. If your system simply does not have enough free memory (video or system) in the first place or runs out during gameplay, then the harddrive is used... Which does cause problems.

That being said, having a faster harddrive like a SSD or 10k RPM drive can and does help during mission loading, or when you run out of video and/or system memory.

My ultimate advice? Spend cash on tons of memory (As it's dirt cheap) and the best video card with the most memory you can afford. 10k Velociraptor drives have come down a lot in price too, are more reliable than SSDs (If not RAIDed) and offer more storage space for the buck.

Yeah, well that's a bunch of hooey, bigtime. I have 12 gig of tri-channel 1600 DDR3 ram on Windows 7 and this sim doesn't access my harddrive for cr@p during a mission.

My microstutters started when I enabled CrossFire-and they freakin' stopped when I DISABLED CrossFire. I didn't do anything else when I enabled CrossFire nor did I do anything else when I disabled CrossFire. Sure love to know how that is a hard drive access issue....

Oh, and yeah, I know that each GPU has it's own 1 gig of memory in a 5970-wondered if the developers managed to do some software magic to benefit from the dual GPU setup and it's obvious that they didn't. Good thing is that it doesn't matter as one GPU functioning in the 5970 runs the game smooth as glass. It's just always nice to go for the gusto...!

SLI/Crossfire does have microstutter issues by nature due to Alternate Frame Rendering. Anyone who says otherwise is lying or an idiot. nVidia even admits this. We warned everyone for over a year that multi-GPU is not all it's cracked up to be. But to show everyone we listen to their requests we implemented it and wasted a bunch of time trying to sort it out before release. I run SLI just fine and I know where to expect stutters as I mentioned in the Graphics Primer. It doesn't bother me a whole lot when I see a small microstutter here and there.

We now have better access to nVidia engineers so we may be able to improve things over time, but team ATI is no where to be found.

Jason

Jason, your advice from the Graphics Primer was spot on and much appreciated. I've messed around a bit with a GTX 590, but the FPS improvement over a GTX 580 just isn't great enough to justify making a change. Your advice to folks to opt for a fast single-GPU card is good advice.

(It is good to hear, though, that you have better access to Nvidia engineers. Your game makes their cards look good.)

Stoopid ATI !!!

I have to admit that the "CrossFire" logo that is displayed in the upper right of my screen when running sims that support Crossfire (WaW, the COD series, etc.) did not show up when I selected the multi-gpu option. I'm guessing that from the total lack of support from ATI (thanks alot) Crossfire wasn't actually implemented at all in this release.

Do you think it would do any good for a "customer" to write them a nastygram requesting alittle support?

That's good to know.

Nice long post, but the bottom line is before 1.20 there was no Sli optimisation in the code for RoF and it in no way benefitted from Sli at all. In my testing of dual cards for RoF I ran exactly the same fps min max avg as a single card in 1.019 and I mean identical. No matter what AA/AF was used or in game gfx settings.

During testing for RoF 1.20, the only benifit from dual cards that I found was with in game super sampling enabled. But SS causes such a drop in performance even with Sli I have decided not to use the ingame option.

BTW this topic is about Sli in RoF not Sli in general so please stay on topic.