VOGONS


First post, by swaaye

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I ran into an interesting LCD quirk. On VGA input these tend to allow >60 Hz refresh. That doesn't mean they actually allow greater than 60 frames per second to output with vsync, however. This gives fast paced games an annoying stutter that makes you think your video card is skipping frames.

I was aware of >60Hz being fakey on LCDs, but I had not seen it firsthand until now. I very rarely use LCDs on VGA, or run them below their native resolution which is usually where the >60Hz options come in and Windows may choose them automatically.

Reply 1 of 8, by 5u3

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I have such a monitor, an old IBM (Lenovo) L200p. It accepts refresh rates up to 85 Hz, but the output is capped to 60 Hz (probably because the panel is rather slow at 25 ms).

This is very annoying when playing fast, smooth-scrolling VGA games (e.g.: Pinball Dreams). And the monitor is especially cruel to scene demos from the early nineties, with all their fast scrollers and frequent mode-switching.

Reply 2 of 8, by VileR

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The most annoying aspect of LCDs for oldschool gaming is the single native resolution and single refresh rate. Haven't seen a flat-panel that can handle 70Hz VGA modes nicely yet.

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Reply 3 of 8, by Jorpho

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Isn't that something you can tweak with VBE somehow? http://home.arcor.de/g.s/vbehz.htm , for instance?

Of course there are games that are written for specific chipsets and don't use VESA modes, but they aren't common, right?

Reply 4 of 8, by swaaye

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VileRancour wrote:

The most annoying aspect of LCDs for oldschool gaming is the single native resolution...

Non-native resolutions are not a major issue as long as the LCD has decent scaling hardware. My 2405FPW which is 1920x1200 and so can fit 4:3 quite well is really quite good at non-native. On the other hand I've seen some 1680x1050 screens that are pretty bad and some cheaper LCDs that just do a jagged pixel stretch!

Reply 5 of 8, by elianda

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I got a Belinea 101735 (111714) TFT from Maxdata. It is rather old, but supports 50 to ~85 Hz (officially 60 to 75 Hz) and runs then also at this refresh rates.
The mode just have to fit into frequencies it is capable off, so at 640x480 it need at least 56 Hz, at 800x600 50 Hz and at 1280x1024 goes upto 85 Hz.
At 85 Hz the LED blinks as a kind of Overdrive Mode indicator, but there is no permanent OSD covering screen areas and it simply shows the signal.
It also shows weird modes and can be switched with one button press to the other input.

From the facts I read here it seems to be one of the better TFTs.
I would consider a TFT that doesn't show the same refresh rate as the input signal broken and send it back.

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Reply 7 of 8, by VileR

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Jorpho wrote:

Isn't that something you can tweak with VBE somehow? http://home.arcor.de/g.s/vbehz.htm , for instance?

Of course there are games that are written for specific chipsets and don't use VESA modes, but they aren't common, right?

You'd still have to depend on how each specific game was programmed to correspond with vsync. Even in the best case scenario, an extremely "well behaved" game would still have to slow down (and potentially screw up timing etc) in order to provide smooth scrolling at 60hz if it was programmed for say 70hz.

swaaye wrote:

Non-native resolutions are not a major issue as long as the LCD has decent scaling hardware. My 2405FPW which is 1920x1200 and so can fit 4:3 quite well is really quite good at non-native. On the other hand I've seen some 1680x1050 screens that are pretty bad and some cheaper LCDs that just do a jagged pixel stretch!

Yeah, there are some exceptional monitors with great internal scaling, but you still kinda have to 'luck out' on one... as opposed to the situation with CRTs. Generally, you'd need to rely on video drivers to do the job, and in most cases those drivers fail to provide decent scaling if you're using the VGA connector, for whatever reason.
I run a dual-monitor setup w/a pair of crappy LG L1953TR screens (1280x1024, aka 5:4!), so I have to rely on pure software scaling, i.e. DOSBox which does it excellently. But if I had a retro rig I'd go with a CRT for sure 😀
(a very good LCD with variable refresh rates / awesome HW scaling would be more than capable - but certain CRT-only tricks such as border / overscan would still be left out...)

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Reply 8 of 8, by 5u3

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Unearthing this thread for an update:
I bought an used HP LP2065, in the hope of getting rid of the stuttering in 70 Hz VGA modes.

Turns out that the LP2065 is even worse than my old IBM L200p. While the L200p just causes regular stuttering (which is annoying enough), the LP2065 drops frames in big chunks and introduces additional screen tearing.

The LP2065 has been recommended for retro usage in the past, how come nobody has ever mentioned this issue? It is really quite obvious and ruins smooth scrolling in any 70 Hz VGA game (e.g. watching Pinball Dreams got me positively seasick after five minutes because of all the screen jerking).

What annoys me most is that many cruddy old 15" TFTs and cheap modern widescreen TFTs don't seem to have problems with 70 Hz. Why is it that older high-end business TFTs can't do the job properly?