Up until very recently, I've played BF4 with only 2x msaa and a mixture of high & ultra settings. With these settings, Afterburner shows my vram usage tops out at around 1520MB in Metro. Perfect for my 1536MB 580. The other week, I decided to revisit BF4's settings and have another play. To my surprise, even with everything set to Ultra and with 4x msaa, the maximum vram usage hasn't increased at all. Now, I'm not complaining but does anyone have any idea what's going on?
MSAA is mathematical operation on pixels / edges, so I doubt increasing it would consume much vram past what turning it on intially does, since you are operating on the same data source. It would however require more processing power since your doing more operations on the same data source. But that's more of a guess than a statement of fact. VRAM I think is more about holding art assets and textures than the operations carried out on them. But again more of a guess.
Would you expect vram usage to be unchanged when switching between "high" and "ultra" settings though?
No I would expect the VRAM to go up, but you've demonstrated that it doesn't. If going Ultra just means doing higher quality pre and post processing on the frame and that can all be done in place on the frame (that is to say the image can be transformed without copying big chunks of it for processing) then it could explain what going on.
That vRAM is bottlenecking you - even at 2x. The 16mb or whatever isn't being used by BF4 will be reserved for the OS or something like that. It isn't increasing at 4x because its already bottlenecked.
You might want to check if you have BF4 Optimised in NVidia settings, I noticed mine had increased the render resolution to 125%, as I suspect their still finding performance gains with newer drivers.
I am running it at 4K Ultra Preset with AA and HBAO turned off and it's only using 3.8Gb of Vram, I have found that the Battlefield games for all there issues seem to not use a stupid amount of resources unlike most other games that look worse. I know with my older cards such as GTX480's, GTX580's, GTX680's and GTX780Ti's it would use the maximum amount of Vram at 1080p and up at pretty much anything from High to Ultra settings.
I tried doing some experimentation on this today and I couldn't get Precision-X to move off of 301MB VRAM usage. WTF? This was me moving from high to utlra, 1080p, to 1440p, increased the render resolution to 200%, exiting and restarting the executable. Wouldn't budge. I do recall seeing it run at around 2300MB of RAM usage during normal game play, that would be around the upper limit at either high or ultra. When I had a 2GB VRAM card I would get massive frame drops as it paged those last few 100 MBs in and out of VRAM. But basically experiment fail. It might need a longer session to start using more VRAM. Edit: Derp. Its updated drivers without a restart, I'll try again tomorrow when I restart the computer. Precision-X is just not giving me real numbers at all.
2174MB usage on high pre-set @1080p 2305MB usage on ultra pre-set @ 1080p Not a massive jump, but reasonable. As I said above I was getting massive frame drops when I was running on 2000MB memory graphics card because the memory just wasn't big enough for me running at 1440p. So it might be worth while to dial things back a little bit for yourself if you notice such spikes.
Yes, I'm gaming at 1080p. I still haven't had a chance to play around with this but I'll make time this weekend. Thinking about it, frame rates are OK (for me) most of the time. They're often maxed (59.?) but usually hover in the 50's & mid-40's. Sometimes they very briefly dip into the 30's and these little spikes can be seen in Afterburner's frame rate graph. I'll see if these correspond with the vram usage spikes.
