Downsampling with VG248QE gsync

[fenderjaguar]

Anyone managed it?

Before it was modified, I could downsample 3840x2160 @ 60hz through display port, now I can't downsample anything at all, above native res. Just get "unsupported input detected".

I can't even run custom frequencies, outside of 60hz, 85hz, 100hz, 120hz and 144hz. Not that it matters too much. But also my custom resolutions (like 1920x1078, which forces particular refresh) won't work with gsync mode, which I can also understand since I didn't specify any other frequency to work with that resolution and therefore anything outside of whatever frequency I specified, ie 30hz - 144hz, only 120hz for example will work. The only reason I mention this is that I created a custom res of 1920x1440 @ 120hz for the 4:3 aspect ratio of halo, and it magically works with gsync? Also, 1920x1440 is technically downsampled, but it also seems to work where nothing else will...

Also, I didn't really poke around much with this monitor before it was modified. But was this really the lowest brightness setting there was, as stock? This thing is making me go blind. I have resorted to using the ULMB mode in 120hz for the desktop all the time, since it appears dimmer. As I understand it, I'm looking at a strobed backlight 24/7 now, it may sound like a stupid question, but is this ok for my eyes/brain?

[Chief Blur Buster]

Anyone managed it?
Before it was modified, I could downsample 3840x2160 @ 60hz through display port, now I can't downsample anything at all, above native res. Just get "unsupported input detected".

The first GSYNC implementation (the GSYNC upgrade) has more limited scaling options in-board, however, you should be able to do more downsampled resolutions if you let the GPU do the scaling before the monitor. Does this problem still happen with you, when you use GPU scaling?

The only reason I mention this is that I created a custom res of 1920x1440 @ 120hz for the 4:3 aspect ratio of halo, and it magically works with gsync? Also, 1920x1440 is technically downsampled, but it also seems to work where nothing else will...

The mode of 1920x1440 is a standard 4:3 resolution found as a predefined resolution in the last 10 years (e.g. 21" CRTs that go up to 2048x1536), so that's probably why it is supported.

Also, I didn't really poke around much with this monitor before it was modified. But was this really the lowest brightness setting there was, as stock? This thing is making me go blind. I have resorted to using the ULMB mode in 120hz for the desktop all the time, since it appears dimmer. As I understand it, I'm looking at a strobed backlight 24/7 now, it may sound like a stupid question, but is this ok for my eyes/brain?

This has been a long recurring problem; I have begun reminding all manufacturers (NVIDIA/ASUS/BENQ) to widen their brightness adjustment range, including a low-brightness 10cd/m2 setting (or even lower); similiar to an iPhone configured to minimum brightness setting. It's good for use in a totally dark room, when your eyes are adjusted to the dark.

With modern 300cd/m2 backlights, and most factory testing done in bright rooms; some monitor manufacturers neglect to test for a dark bedroom or a home office at night; and do not properly include lower brightness ranges, for brightness-sensitive people.

The strobe backlight is not an eyestrain problem if you don't feel eyestrain. Only some people get flicker eyestrain. It is a "pick your poison effect" on many monitors:
-- There are people around here who get more eyestrain from motion blur than from flicker.
-- There are people around here who get more eyestrain from flicker than from motion blur.
-- There are people around here who get more eyestrain from brightness than from flicker.
-- There are people around here who get more eyestrain from flicker than from brightness.
-- etc.
This is why the LightBoost FAQ has both entries for:
"Why Does LightBoost Have MORE Eyestrain?"
"Why Does LightBoost Have LESS Eyestrain?"
e.g. http://www.blurbusters.com/lightboost/testmonials and http://www.blurbusters.com/lightboost/faq

One thing to know is that the VG248QE had PWM (high-frequency flicker for brightness dimming) before the GSYNC upgrade, but the VG248QE goes PWM-free after the GSYNC upgrade. So apparently, you don't get eyestrain from PWM if you never got eyestrain on the pre-upgraded VG248QE, and if you are getting eyestrain now, then your eyestrain is probably more brightness-related than flicker-related. However, there are so many causes of eyestrain that affect different people.

So pick one of the two: blur-free or flicker-free.
Due to engineering consideration, it's technologically not currently (yet) practical to have both simultaneously, for a single blur-sensitive/flicker-sensitive individual. (Blur-free requires low persistence, e.g. 2ms, which requires either 2ms strobe flashes or 2ms frame lengths (e.g.500fps@500Hz) which is not possible yet on computer monitors). (Note, persistence is not the same thing as GtG transitions. GtG is not the cause of motion blur on newer LCD monitors). Now, throw in a wide brightness range, and the engineering considerations become more complex...

[fenderjaguar]

The first GSYNC implementation (the GSYNC upgrade) has more limited scaling options in-board, however, you should be able to do more downsampled resolutions if you let the GPU do the scaling before the monitor. Does this problem still happen with you, when you use GPU scaling?

It's the only option available to me. From nvidia control panel, GPU scaling is the only thing selectable from the drop down. There is no display scaling now. I always used GPU anyway.

The mode of 1920x1440 is a standard 4:3 resolution found as a predefined resolution in the last 10 years (e.g. 21" CRTs that go up to 2048x1536), so that's probably why it is supported.

Yeah, but 2560x1440 is a pretty predefined res as well, but I'm not having any luck with it.

Thanks for your post though, very informative. I appreciate that thanks

[fenderjaguar]

OK, so I was finally able to downsample 2560x1440 @ 60hz. I don't really know how I've done it, but it had something to do with connecting my old monitor (LG W2363D), which had a load of downsampled resolutions already created for it. When I cloned the displays it seemed to work and now the 2560 res has stuck for the g-sync monitor, even without the LG connected. Still can't do any other resolutions than that, though...

So G-sync does work with the 2560 res, but it's very flickery and seems to cut out. Almost felt like I was risking damaging the monitor. I think there needs to be different drivers, maybe when 2560 g-sync monitors come out later this year it'll benefit people who are downsampling as well?

[masterotaku]

Sadly, it's difficult to downsample at high refresh rates, but there's a new and partial solution still in alpha phase. Durante (the awesome guy that fixed Dark Souls) has made a new tool to make downsampling possible in DirectX 9 and DX9EX games in general: http://blog.metaclassofnil.com/?p=487
Some of the options like SSAO are obviously only for Dark Souls 2 (I think), but downsampling works for other games. I've tried it in Dishonored, for example, and it worked with 3840x2160 internal resolution at whatever refresh rate (I was using 95Hz at that moment, but it works at any frequency). Give it a try.

Quoting something from his blog:

"As you can see above, GeDoSaTo works. It currently sports the following features:

Downsampling, better than any other solution:
Essentially no resolution limits (beyond those of the GPU)
Downsampling from more than 4x the resolution is useful (multi-stage downsampling)
Selection of downsampling methods (not just bilinear sampling)
Downsampling in linear color space
Support downsampling to high-frequency (e.g. 120 Hz or 144 Hz) target modes
Not limited by display hardware
Take screenshots of either the pre-downsampled full buffer or the actual image displayed on screen (automatically sorted in per-game folders!)
Generic texture overriding for all textures loaded using D3DX
It uses a far more solid injection and interception method than my earlier efforts
However, there are plenty of bugs, limitations, and many things I would like in order to call it “complete” are still missing:

Only DX9 and 9ex supported, and only in 32 bit. No DX10, 11 or OpenGL, and no 64 bit games
No per-game configuration yet
No plugin or scripting system yet, to allow everyone to implement game-specific graphical features"

[fenderjaguar]

Sadly, it's difficult to downsample at high refresh rates

I understand that. But that's not actually the issue here. Before G-sync, I was desperately trying to downsample at high refresh rates too, because running in 120hz mode diminishes tearing. G-sync makes all this refresh rate battle redundant though, since it makes the refresh whatever your frame rate cap is. And with downsampling I'd be looking at a 40 fps cap and therefore 40hz refresh anyway. It just doesn't matter about that.

But thanks a lot for this internal downsampling info you have given to me. I'll check it out. Thanks again

[fenderjaguar]

OK, so I successfully used the tool with half life 2. Would never use it with that game in real life, obviously, as the MSAA + enhanced SSAA transpartent textures have everything covered there. But it works and more importantly it really works flawlessly with g-sync and 144hz g-sync. Quite impressive, I wish nvidia would officially offer us something like this.

Interestingly, the performance hit from 7680x4320 is greater than with 4x4SSAA, which as I understand it is rendering the same resolution internally...

I just wish I could get it to work with GTA IV, which is pretty much the only game I'm interested in downsampling at the moment.

[ManuelG_NVIDIA]

Anyone managed it?

Before it was modified, I could downsample 3840x2160 @ 60hz through display port, now I can't downsample anything at all, above native res. Just get "unsupported input detected".

I can't even run custom frequencies, outside of 60hz, 85hz, 100hz, 120hz and 144hz. Not that it matters too much. But also my custom resolutions (like 1920x1078, which forces particular refresh) won't work with gsync mode, which I can also understand since I didn't specify any other frequency to work with that resolution and therefore anything outside of whatever frequency I specified, ie 30hz - 144hz, only 120hz for example will work. The only reason I mention this is that I created a custom res of 1920x1440 @ 120hz for the 4:3 aspect ratio of halo, and it magically works with gsync? Also, 1920x1440 is technically downsampled, but it also seems to work where nothing else will...

Also, I didn't really poke around much with this monitor before it was modified. But was this really the lowest brightness setting there was, as stock? This thing is making me go blind. I have resorted to using the ULMB mode in 120hz for the desktop all the time, since it appears dimmer. As I understand it, I'm looking at a strobed backlight 24/7 now, it may sound like a stupid question, but is this ok for my eyes/brain?

We are investigating this. Will update this thread when we have more information

[fenderjaguar]

We are investigating this. Will update this thread when we have more information

Oh excellent. I appreciate that, thanks.

[fenderjaguar]

I've finally managed to downsample 2560x1440 @ 100hz and get it working with g-sync.

When creating custom res with NVC, it seems that you need the desktop to be running at the same frequency as what your downsampled res is going to be. So if you're creating a 60hz downsampled res, then make sure your running in 1920x1080 60hz mode when creating it.

2560x1440 @ 60hz with g-sync mode is very flickery and bad. I don't know why. But if you create the same res at 100hz and run in g-sync, it seems to work perfectly.

I can get 3840x2160 @ 60hz, but it fails after about 30 seconds. so be careful, if you don't have another monitor, because it can be difficult to get it back to a resolution which doesn't give a black screen. it will create with the auto settings, but not with the 3600 x 2025@60 Hz manual timings like in this thread (that worked fine through dvi d on the LG w2363d)

http://www.neogaf.com/forum/showthread.php?t=509076

I would have needed to get 3840x2160 running at 100hz to work with g-sync anyway. Since I can't even get it stable at 60hz, I don't think it's worth bothering with.

Also, now i have created an 85hz 2560x1440 and that works perfectly with gsync as well. Then I ran a game in all three frequencies (including 60hz) and they all work perfectly. So I can't understand why the 60hz one was flickering before...