GammaLyrae wrote:Although I suppose if the game is running on your PC with a Windows refresh rate of 240hz and no Freesync is in play, then the monitor would still be doing the fastest scanout possible, offering 1:1 performance with a fast, 60hz native display...right?
Correct.
GammaLyrae wrote:Maybe even faster.
Theoretically possible.
The LG monitor supports frame delivery in 1/280 sec using the VT1302 trick (max dotclock possible)
I don't know if the panel scanout is 1/240sec or 1/280sec.
GammaLyrae wrote:Assuming what you're saying about the scanout being synchronous in a locked 240hz scenario is true. (IE: The 60fps frames are duplicated 4 times @ 240hz, rather than the monitor only updating 60 times per second)
Hold it, I never said that.
<Techncial: How It Works>
What I meant to say was 240Hz monitors does a partial buffering of the pixels arriving on the cable and then scans it out at high velocity.
Fundamentally - pixels are transmitted over the cable sequentially, one scanline at a time (rows of pixels), top-to-bottom. This is called rasterization, the art of "scanning out". Serializing an image over a wire has been done roughly this way (both analog and digital) for almost a century, and the standard scanout direction is top-to-bottom.
Clarifying The Variables To Avoid Misunderstanding
Display = Most 240Hz panels (at the moment)
Mode = Standard 60 Hz 1080p (like a console)
VRR = None
Cable Point of View
Frames are arriving in a slow-scan, taking 1/60sec to deliver a frame top-to-bottom
Panel Point of View
Some panels do synchronous scanout, but something weird happens with current 240Hz panels:
They can only refresh fast!
It must display a refresh cycle top-to-bottom in 1/240sec. For some weird reason, it can't slow-scan. It's refreshing only once every 1/240sec. It simply pauses 3/240sec between refresh cycles (no extra refresh cycles) -- the static image just idles in a sample-and-hold manner, merrily keeping displaying the image that was refreshed before. No repeat refreshing is occuring. It's just longer pauses between fast-scanouts.
How Do You Display a Refresh Cycle Quickly From a Slow Frame Delivery Over Cable?
Yup. You have to buffer the slow cable scanout before you can do the fast panel scanout. It does a 3/4 buffering (basically buffers for 3/4ths of 1/60sec) -- roughly 12-13ms of buffering then it begins the fast scanout, while still buffering the final scanlines. The fast scanout (panel) meets the slow scanout (cable) by the time the final pixel is delivered over the cable. This is an internal "scan conversion" to make a slow scanout signal compatible with a fast-scanout-only panel.
Result: More lag for top edge than a 60Hz monitor.
Leo Bodnar Lag Tester would reveal:
Top: 3/4ths of a refresh cycle more lag than bottom edge.
Center: 1/2 of 3/4ths of a refresh cycle more lag than bottom edge
Bottom: Approximately full cable-original refresh cycle lag + partial GtG lag + cable lag (usually ~1/60sec + 1ms + 1ms)
Is this true for all panels?
No. Some panels can vary scanout speed on the fly. Many 144Hz 1080p panels can scanout synchronously with the cable scanout of a fixed-Hz signal, and their scan velocity will increase (without increased refresh rate) using Large Vertical Total tricks, which is why strobe crosstalk gradually reduces when doing Large Vertical Total tweaks on the 1080p 144Hz BenQ monitors.
Another different way to understand the fast-scan-and-long-pauses-between-scans is Large Vertical Totals which is a common trick to reduce strobe crosstalk
</Techncial>