Kevin Firth 114 Posted May 15, 2015 Report Share Posted May 15, 2015 Whos going to be the first to report back on performance under an SLI configuration then please? 1 Link to post Share on other sites
MyPC8MyBrain 273 Posted May 15, 2015 Report Share Posted May 15, 2015 lol, about time W00T Link to post Share on other sites
ddavid 149 Posted May 15, 2015 Report Share Posted May 15, 2015 Kevin, I was under the impression that SLI didn't improve framerates on FSX - am I wrong? Maybe P-3D will overcome this? Cheers - Dai. Link to post Share on other sites
Christopher Low 63 Posted May 15, 2015 Report Share Posted May 15, 2015 It's of no interest to me. I ain't forking out 200 quid for another graphics card! Link to post Share on other sites
Kevin Firth 114 Posted May 15, 2015 Author Report Share Posted May 15, 2015 It remains to be seen Dai, the appearance of a formal SLI profile implies some benefits at least, ultimately it will depend on each system really I think, particularly on the time of day &weather and your CPU. If you are not CPU limited at any point SLI will remove your GPU bottleneck and perhaps give you more frames. In CPU limited scenarios I imagine SLI will give you much more consistent time between frames and therefore a much smoother framerate (ie much fewer stutters) even if the FPS doesn't increase. Having said that Ive never used SLI or even any nVidia GPU, so thats just common sense speculation on my part. Unless youve got money to burn my recommendation would be to wait and see what results other people get! Cheers K My moneys on 2x GTX970's turning out to be the most cost effective SLI choice. I was considering looking at an R9 390X as a cheaper single GPU option but 2 970s will prob be cheaper and better. Dai, FSX was never coded with multi GPU setups in mind I think, whereas LM have worked with nVidia to bring this about. I'd bet there'll be significantly more improvement in P3D under SLI than FSX Link to post Share on other sites
Christopher Low 63 Posted May 15, 2015 Report Share Posted May 15, 2015 I definitely wouldn't look at an AMD GPU, Kevin. Popular opinion is that they aren't as good as Nvidia for P3D or FSX. I tend to agree that 2x GTX970s would be a good choice for anyone who does decide to go down the SLI route, although Rob Ainscough (beta tester for Lockheed Martin) has just purchased a second Titan X!!! Link to post Share on other sites
Kevin Firth 114 Posted May 15, 2015 Author Report Share Posted May 15, 2015 Chris I dont believe all the hype about nVidia being much better. My AMD cards have performed well, but now there is a pressing case to consider nVidia as better simply because SLI exists for P3D but crossfire will never work. Popular opinion is precisely that, opinion, and is often founded on little more than fokelore and wishful thinking. Rob A's purchase of a second Titan X only proves he can afford several of them, but I would be persuaded by the performance results he posts if they show improvement as I know Rob is objective about his testing Link to post Share on other sites
Christopher Low 63 Posted May 16, 2015 Report Share Posted May 16, 2015 I remain sceptical as to just how much of a difference SLI will provide to framerates in P3D, although I would be quite happy to be proved wrong. I just can't help thinking that it will be the CPU that determines the upper performance limit in SLI systems. Link to post Share on other sites
Kevin Firth 114 Posted May 16, 2015 Author Report Share Posted May 16, 2015 Yes Chris, but much more consistent time between frames will mean that visually you wont need as many FPS to maintain the appearance if smooth flight Link to post Share on other sites
MartinW 0 Posted May 17, 2015 Report Share Posted May 17, 2015 I remain sceptical as to just how much of a difference SLI will provide to framerates in P3D, although I would be quite happy to be proved wrong. I just can't help thinking that it will be the CPU that determines the upper performance limit in SLI systems. Flightsim is CPU dominant. But yes, the graphics card is important too. And these days of course, now that we are using graphically demanding scenery and weather add-ons, even more so. In regard to SLI, it was always said that it only benefits FSX at very high resolutions and AA settings. The point though, is that many of us are indeed now using higher resolutions and AA settings, because we have powerful enough graphics cards to do so. In addition of course, many of us are using CFG tweaks like BP=0, whereby data is fed directly to the graphics card, bypassing the buffer. Not sure how that might impact the results. So it seems that SLI might offer more of a benefit now than it used to. No miracles though. From Phil Taylor... SLI and Crossfire happen in the driver. The app stays out of the way and, as long as the app doesn’t do any of the 2 or so "bad things" that could break SLI it just works, see Note 1. The main issue is FSX is CPU bound so the extra GPU doesn’t provide any benefit until fill rate, as determined by resolution and AA settings, drive past the CPU-boundness. So SLI doesn’t benefit FSX much except at extreme resolutions with high AA. This is borne out by the review “Real-World Gaming CPU Comparison with 8800 GTX SLI”. This article proves at 19x12 or 25x16 with 16xAA on the Intel CPU, the fill rate requirement is high enough to counterbalance the CPU-boundness and show some benefit for FSX. And these conclusions are borne out by the community, see Note 2. On AMD, the CPU is enough slower enough that even with those fill-rate settings the CPU side of the performance cost equation still dominates. As another note, ExtremeTech here indicates other games have varying success with SLI. This shows FSX wasn’t showing a negative impact like some titles. True we could be better, but it is worthwhile for the community to realize that these issues are not occurring in FSX in isolation. If we get decent impact from SP1 on the CPU side, then SLI scenarios should get that much better. http://blogs.msdn.com/b/ptaylor/archive/2007/03/03/fsx-more-on-sli-and-multi-core.aspx Link to post Share on other sites
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