Directx 9 and 4k (14.9.2) Issue - - UPDATE - - [Quad + 4k + Vsync on was the issue]

[KaRLiToS]

This morning I decided to try my middle monitor, which is the Samsung U28D590D (3840x2160) 4k.

I wanted to try Skyrim and since its multi-monitor support is broken, I said why not try 4k after 5 months of owning that panel.

So I launched Skyrim at 4k just to realise tremendous amount of stutter. I checked google to find a solution and found nothing. Tried the same settings but at 2560x1440 and everything was fine.

Then I tried Borderlands the Pre Sequel at 4k to notice the same issue. I then tried Grid autosport and it was fine, tried Valley benchmark and it was fine, Ryse son of Rome was fine, Sniper Elite 3 = fine ....then I tried Saint-Rows IV and the same stutters.

My conclusion is that directx 9 as some issues with 4k?

Am I missing something, I'll try previous driver versions but I wonder if its directly tied to directx 9?

Thanks for helping me out.

 

[96Firebird]

I'm not sure if AMD ever worked on frame pacing for DX9 @ 4K, here is a thread from July where it is talked about: AMD Frame Pacing: Any word on DX9 support?

 

[f1sherman]

DX9 frame pacing was never done as far as I know.

But that does not sound like frame-pacing issue, and on top of that SR IV is DX11

 

[alcoholbob]

Are you using displayport or hdmi.

 

[KaRLiToS]

Display Port

If I run 1440p on the same monitor, smooth as butter, with 4k on those games... it is stuttering (mega stuttering)

 

[soccerballtux]

could just be, video card not have enough bandwidth??

 

[KaRLiToS]

Ok so after numerous amount of testing, I realized that I was completly wrong with the directx 9 vs directx 11 hypothesis.

I tried 4k with
-Single card, no stutter.
-CrossFire, no stutter
-TriFire, no stutter
-QuadFire, mega stutter

The issue I have ressemble to this.

I noticed that the FPS was always locked at 60fps so I was wondering what the hell is that stutter.

To my surprise, I decided to turn off Vsync and Voilà, it was solved so I wonder how come: QuadFire + 4k + Vsync on = Stutter

BUT

QuadFire + 8040x1440 (Triple 1440p) + Vsync on = NOOO Stutter at all

So apparently, AMD never tested Vsync on with Quad + 4k ???????????? I might be wrong but it work FLAWLESSLY with Vsync off.

So my conclusion:

Vsync and 4k work with Single, Dual and Triple cards but not Quad.

Anyway, I still have many options, disable one card or run with Vsync off, anyway, in most games, with 3 cards I get more than 100 fps at 4k so disabling a card is not that bad.

I also noticed in Sniper Elite 3 that with Quad and 4k:
-Vsync on I get a lock 60 fps and my Kill a watt indicates 900 watts
-Vsync off I get around 200 fps and my kill a watt indicates around 1300watts.

 

[lavaheadache]

Have you tried a frame cap?

 

[KaRLiToS]

Have you tried a frame cap?

With Radeon Pro? I have thought of it but I didn't try.