MiSTer FPGA Forum

You can set custom resolutions in core specific config.

For instance, 4x integer mode (1536x1024) with CVT-RBv1 timings for use with Irem M62/M72 specifically:

[misterlaggy]
video_mode=1536,48,32,80,1024,3,10,14,98068

This is awesome. What is the fastest modern screen someone has found? I recently bought a cheap acer lcd. KA272. top square at 1080p comes in at around 5.5ms. Not bad. I also have a pvm hooked up too and that came in around 1ms as expected.

Before I got the mister laggy I recorded a mario jump on both of these in the same frame at 240fps and mario jumped one frame later on the KA272. So 240fps is around 4.2ms per frame. So I was pretty sure the lcd was in the 5ms-8ms range. Nice to get confirmation with this device.

As for playing one or the other. I can't really feel much of a difference in latency, but to my eye the PVM image is usually way better but depends on the core. A good example for me is ghosts n goblins arcade which looks like crap on the lcd compared to a PVM next to it. I like the setup though because running update all or other stuff doesn't show up on the PVM and I can easily tate the lcd. So yeah having a lcd plus a crt is the way to go for me.

Just wanted to say I finally had a chance to test this out, and it worked great. Using it I found out that an 8+ year old BenQ 1080p monitor I recently got for free from work only had 5 - 8 ms of lag.

I have a TV without VRR support and it has low latency only with 60 or 50Hz signal.

Since my TV lacks ability to tell the input signal refresh rate, trying to figure out which cores match this description is proving tricky. I don't quite know what precisely qualifies as "flat 60Hz". Using CVT-RB, practically nothing is ever precisely 60Hz, but besides not knowing the TVs opinion on it, I also don't understand how MiSTer itself treats cores and if it actually uses CVT-RB (restricting pixel clock granularity to 0.25MHz) or not.

My feeble brain is hopelessly insufficient for solving this. Can someone help me out?

One solution that comes to mind would be ability to tell MiSTer Laggy core to output exactly X * Y @ N Hz, so it could simulate any other core. At least it would take any guessing out of the equation. For convenience, eg. menu option "emulate: Mega Drive" would make the core output 320x224 @59.852 Hz (?), and regular MiSTer.ini options would apply.

Well alright, I came up with a roundabout way to determine if a given core runs with low latency on my TV or not. I have another VRR capable monitor and an HDMI splitter, and forcing VRR on happens to work for both, TV just ignores it. Cores with 240p test suite are simplest to test since it has a lag test tool for this specific purpose, but taking photos of game feed is also sufficient to find if they differ.

It seems that any core outputting a refresh rate that rounds to 60Hz (59.5-60.4?) gets low latency, rest do not. In practice, this means all major console cores, but only a small number of arcade cores. Even NeoGeo gets low latency only in AES mode; output from MVS mode has a tiny bit lower framerate, for whatever reason.

Has anyone had an issue where launching MiSTer Laggy locks up the MiSTer? I'm using the latest release (20231014), but have tried all three available releases and the behavior is the same.

Setup:
MiSTer with dual SDRAM (128MB module and 32MB module)
Digital IO board
Dell U2412M connected through an HDMI to DVI cable
Laggy connected to the user port through a USB A to C cable

Immediately after launch, the MiSTer stops responding and the monitor loses connection. Hitting the physical reset button on the IO board does nothing, and in some cases the LEDs on the board blank out entirely.