NVidia 970 running slow when VRAM approaches limit

[Keith Smith]

Very interesting. I was thinking of upgrading my video card in the near future, too:
http://www.pcworld.com/article/2887234/ ... mance.html

[Pieces]

I've been using a 970 for a few weeks now. I knew about the 3.5 GB max performance memory limit before buying, but decided that the $200 for the 980 wasn't worth it.

So far, it is a definite improvement over my 760 2GB, but not quite as spectacular as I'd hoped. Shadows absolutely destroy the framerate in X-Plane on this card. I can't even have 3D cockpit shadows on without dropping 10+ fps. I can experiment a little this evening and see what I would have to do to get global shadows running at 20+ fps.

Interestingly, antialiasing and ansiostropic filtering have very little impact on frames. I only see a 1-2 fps change between off and max for both of those.

[Keith Smith]

Reece, shadows require the scene to be rendered internally more than once if I understand correctly so a frame drop isn't surprising. The big question is what the framerate was before the shadows were introduced. If it's high enough, then losing 10fps is fine. If you were at 25 to start with, then the drop to 15fps is going to be ugly.

[Pieces]

Right. My problem is I don't want to lower the other rendering settings far enough that a 10+ drop is acceptable. That's why I'm going to do some experimenting to see what type of options need to be set to end up at 20+ with global shadows enabled.

[BK1984]

Been running the 970 for a couple weeks now with X-Plane pushed pretty hard. I've experienced none of the reported issues though I don't know how often my usage goes above 3.5. I rarely dip below 30 fps even when weaving in and out of the OSM skyscrapers in downtown LA in the Carenado King Air. Using a GPU monitor the memory used usually dances between 3 and 3.5 GB. I've yet to really run any tests to see what happens once it goes over 3.5.

[Pieces]

Mind posting your rendering settings?

[BK1984]

Mind posting your rendering settings?

Sure.

[fivechickens]

I'm running a GTX970, and depending on my situations I can spike past 3.5GB memory usage but the framerate drop is already compounded by the stupid amounts of AA I have to run in order to get the ram usage that high.

System Specs:

GTX 970 G1
i5 2500k @ 4.6ghz
32GB PC2133 DDR3 Ram
XP10 on SSD stripe

I run at 2560x1440p at 32bit, average around 45-50fps, drops a bit ~10fps when I'm streaming as I use NVENC.

[Keith Smith]

I'm moving from a Radeon 7900 to a GTX970 tomorrow. Pretty excited, it's the first hardware upgraded in several years.

CPU is 7-3930K @ ~4.5Ghz

[wmburns]

Keith,

I'm currently running a GeForce GTX 750 Ti 2GB. Getting X-Plane frame rates 45-60 FPS (HDR on). This on a Haswell i5 CPU/Z87 MB.

I'm about to show my age here. But I have personally struggled with the idea of spending 1,2, or 3 times more on a video card than what my WHOLE CPU/MB system costs. Even buying the GTX 750 on sale for about $140 part of me died.

I call myself tech savvy when it comes to PC's and PC hardware. However I have to admit to having some serious "dumb and dumber" moments when it comes to comparing the various "lines" of video cards (new/old/legacy). IMO the model numbers are deliberately designed to confuse.

I have to admit to making buying/comparing decisions based mainly on $$'s.

That's why I'm really interested in hearing about your experiences with this upgrade. IMO it's a great "test case" as everything remains the same with the exception of the new video card.