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Adaptor DP to VGA needed due to lack of VGA/DVI-I port

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Re: Adaptor DP to VGA needed due to lack of VGA/DVI-I port

Postby RealNC » 12 Feb 2018, 12:53

nuninho1980 wrote:Thank you. :) But I've knew G-Sync/FreeSync don't support any CRT because any CRT has always FIXED vertical frequency only but yes GUESS VRR. ;)

The "hack" actually allows some CRT monitors to support FreeSync. Contrary to popular belief, CRTs are not fixed refresh by nature. However, many CRTs, especially "modern" ones, do force an artificial fixed refresh which makes hacking freesync into them impossible.
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Re: Adaptor DP to VGA needed due to lack of VGA/DVI-I port

Postby nuninho1980 » 12 Feb 2018, 15:03

RealNC wrote:The "hack" actually allows some CRT monitors to support FreeSync. Contrary to popular belief, CRTs are not fixed refresh by nature. However, many CRTs, especially "modern" ones, do force an artificial fixed refresh which makes hacking freesync into them impossible.
Ok... But when framerate is dropping in game/application, "fps" is following Hz (but min 50 Hz for most CRT's), ok?
Last edited by nuninho1980 on 25 Feb 2018, 19:51, edited 1 time in total.
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Re: Adaptor DP to VGA needed due to lack of VGA/DVI-I port

Postby Chief Blur Buster » 25 Feb 2018, 01:17

nuninho1980 wrote:
RealNC wrote:The "hack" actually allows some CRT monitors to support FreeSync. Contrary to popular belief, CRTs are not fixed refresh by nature. However, many CRTs, especially "modern" ones, do force an artificial fixed refresh which makes hacking freesync into them impossible.
Ok... But when framerate is dropping in game/application, "fps" is following following Hz (but min 50 Hz for most CRT's), ok?

Inherently, FreeSync is just a variable sized VBI.

Image

FreeSync is simply a variable-thickness VBI between the refresh cycles.

By using ToastyX to force VRR out of HDMI, then using an HDMI-to-VGA adaptor -- some people have succeeded in getting FreeSync to successfully function with a CRT within a tight range. There are several MultiSync CRTs which sync to any (normal) fixed Hz in a range.

I used PowerStrip almost twenty years ago to configure custom refresh rates on CRTs!

Also, vector CRTs were variable refresh rate -- the 1982 Star Wars videogame was a variable refresh rate game, the tube started to flicker more as more vectors started getting drawn.

Some multisync raster CRTs are fast-reacting enough to slew their refresh rate in realtime (And don't automatically blank during gentle refresh rate changes), and worked fine with FreeSync -- with a few minor side effects (tighter ranges, some tubes had occasionally rolling picture if refresh interval changed too fast).

Intrisinically, nothing prevents forcing a multisync CRT to work with FreeSync as long as the Hz range is within its existing MultiSync range.

Google "multisync CRT", they existed for decades.

Those are NOT fixed refresh rate CRTs. NEC is the most popular, but many manufacturers did it, Sony, Samsung, Eizo, etc. Any refresh rate you wanted between "X Hz" and "Y Hz". A fully continuous range. Normally you outputted a custom unvarying refresh rate to them. But what many people don't realize is that many of them actually can accept a varying refresh rate, too -- since FreeSync is simply an analog-compatible modification to a video signal -- via a variable-sized blanking interval -- and thus, can be forced into a CRT, which sometimes actually works.

They were never designed to accept a continuously-varying refresh rate, but at least the refresh rate changes are very stable -- the horizontal scanrate stays the same, the dotclock stays the same, you're simply adding/removing scanlines from the VHOLD black bar -- as the method of varying intervals between refresh cycles. This is the most gentle possible way to vary the refresh rate, and apparently, several CRTs are quite happy with it.

I purchased a multisync CRT (Samsung SyncMaster 17GLSi) back in 1995 which could sync to pretty much any refresh rate in a continuous range -- If I sent it 63.5Hz (Fixed Hz), it works immediately at that refresh rate. If I input 82 Hz, it works too. You had a min/max horizontal scanrate, and a min/max vertical scanrate. As long as the signal was compatible, it would display it. A FreeSync signal is able to stay within these specific specs of a multisync CRT. What the CRTs were never designed to do is accepting continual refresh-rate changes (as gentle as it may be) -- they weren't expecting dozens of refresh rate changes per second -- but they are extremely gentle changes (thanks to fixed horizontal scanrate) -- so FreeSync apparently works fine on several multisync CRTs.

Multisync CRTs is the the type of CRT that sometimes actually unexpectedly works fine with FreeSync -- the condition is that their circuits need to react fast enough to refresh rate changes -- and that they don't trigger their electronic refresh-rate-change blackout/blueout (blank screen during mode changes) whenever the refresh rate varies continuously.
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Re: Adaptor DP to VGA needed due to lack of VGA/DVI-I port

Postby nuninho1980 » 27 Feb 2018, 10:55

Ok but I don't want G-Sync - I get black screen during 1 second because OSD of my CRT monitors (Samtron 70E 17", Samsung 957MB 19" (current used), Samsung 1100P+ 21" and 1100DF 21" - these 2 died :() prevent "explosion" (horizontal/vertical frequency changed).

I remember - in 1995, I was 15 years old :D and I got artifacts/glitches quaking and/or flickering at 1280x1024@60Hz lol xD on my CRT monitor 14" AOC (year 1993) with max resolution 1024x768@60Hz (but not sure) for the OUT OF RANGE of vertical and/or horizontal frequency. :)
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