Enabling 144hz for Asus PG278Q on AMD gpu

[erssn]

Hello @ToastyX and all!

I have been lurking the forums for a while, trying to solve this problem with my Asus pg278q 1440p 144hz gSync v1 monitor.

The main problem is that back in the day, AMD 290/290x didn't work well with the standard timings of the monitor and AMD restriced the timings in the driver, basically prohibiting the use of 144hz with this monitor if using an AMD gpu. The monitor now just supports 120hz with AMD out of the box.

I found a smart kiddo on the Asus forums managed to find new timings that worked both with the GPUs and the monitor. See here: Asus ROG forums. I tried this solution with my Vega 64 and it worked beautifully!! Now, 7-8 months later I'm sitting here with my new RX 5700 XT and I can't f*cking get it to work whatever settings a enter into CRU. If a use the timings from the Asus thread, the 144hz option does not even show up in windows, however with "LCD Native" settings in CRU or with just an incremental increase to vertical blanking it shows up as an alternative. However, the monitor then gives "Out of range" when enabling 144hz.

Another guy seems to have hade the same issue as me in the CRU thread. See here: CRU Thread post 5119. ToastyXs answer is that probably AMD started restricting low Horizontal Blanking values to get rid of the problem with 290/290x. Reasonable. Soon thereafter I believe ToastyX added "HBlankingLimit remove" to the ATI/AMD Pixel Clock Patcher tool, since its states "HBlankingLimit 56" which is the same limit as post 5119 is referring to. I still have this issue, even though applying the pixel patch.

However: I believe now that there is a Vertical Blanking Limit apperant based on the many problems people are having with high memory clock speeds on RX 5700/RX 5700XT with 144hz. See here: Reddit thread. The main issue with the high memory frequency is low Vertical Blanking, = AMD restricts the driver from working with low vertical blanking, and therefore the compatibility between RX 5700XT and PG278Q 144hz?


TLDR: The Asus Rog forum custom resolution fix was working with my Vega 64. After switching to RX 5700XT i cannot use 144 hz with PG278Q anymore. Is there maybe a new V.Blanking limit in the driver? Is it possible to update/edit the pixel patcher tool to remove it, or regedit?

I did my research but now I'm stuck. Does anyone have any input how I can move forward? I really want 144 hz instead of 120 without buying nvidia or a new monitor (love it). (I have a new 1.4 DP cable since 2 days ago, same issue).

Pls help /erssn