MXP122@psuvm.psu.edu (Malzor) (02/12/91)
OK, I remember some talk a while back about flicker in this mode with a Nec
Multisync 3D and I COMPLETELY ignored it because my windows worked great in
this mode. Well, I just updated my system with memory and can now run in
386 enhanced mode. Now there is flicker on my Nec. How do I get rid of this?
It is OK if I then run it in real or standard mode. . .
any advice???
Thanks.jporter@twaddle.dell.com (Jeff Porter) (02/12/91)
In article <91042.221913MXP122@psuvm.psu.edu>, MXP122@psuvm.psu.edu (Malzor) writes: |> OK, I remember some talk a while back about flicker in this mode with a Nec |> Multisync 3D and I COMPLETELY ignored it because my windows worked great in |> this mode. Well, I just updated my system with memory and can now run in |> 386 enhanced mode. Now there is flicker on my Nec. How do I get rid of this? |> It is OK if I then run it in real or standard mode. . . |> |> any advice??? |> |> |> Thanks. The flicker is a function of the refresh rate of the display which is in turn controlled by your graphics card. To get 1024x768 resolution, your graphic cards (as do most VGA/ super VGA) use interlaced mode. In interlaced mode, the graphics card updates the even scan lines and odd scan lines during alternating frames. The net effect is that the even scan lines are updated 30 times a second and the odd lines are updated 30 times a second. At this low speed, some flicker is noticable, especially with high contrast images. To correct the problem, you will have to update your graphics card (ouch) *and* your monitor (OUCH!!). The Nec 3D is a great monitor (I have one at home!), but it isn't fast enough to support non-interlaced 1024x768. (In non-interlaced mode, the whole screen image is updated every 1/60th of a second. The scan lines are updated sequentially from top to bottom.) Jeff Porter Dell Computer Corp.
nsus_cif@troi.cc.rochester.edu (Nick Susch) (02/13/91)
In <15085@uudell.dell.com> jporter@twaddle.dell.com (Jeff Porter) writes: >In article <91042.221913MXP122@psuvm.psu.edu>, MXP122@psuvm.psu.edu (Malzor) writes: >|> OK, I remember some talk a while back about flicker in this mode with a Nec [Stuff about problem with filcker in 1024x768x256 mode when running in enhanced mode] >|> Thanks. >The flicker is a function of the refresh rate of the display which is in >turn controlled by your graphics card. To get 1024x768 resolution, your >graphic cards (as do most VGA/ super VGA) use interlaced mode. In interlaced >mode, the graphics card updates the even scan lines and odd scan lines during >alternating frames. The net effect is that the even scan lines are updated >30 times a second and the odd lines are updated 30 times a second. At this >low speed, some flicker is noticable, especially with high contrast images. I assume that the first person is using a Tseng ET4000 board. I also have this board and have this annoying flicker problem. I know that 1024x768 is interlaced, but the flicker is horible under windows. If I exit windows and run a program in 1024 mode, I *can* tell it is interlaced, but it is *very* slight, and the screen in very easy to read. But as soon as I start up windows in 386 mode, something happens to the card. The flicker becomes unbarable. I have discoverd, using the option of my NEC 3D which saves the screen setting to each particular sync, that the 1024 mode under windows is a different sync then the "regular" 1024 mode. Does anyone know why this happens? It's like their is two modes on the ET4000, regular interlaced, and really slow interlaced, and windows picks the wrong one. Any help would be appreciated. --- "And when I have understanding | /\/ick Susch - University of Rochester of computers, I will be the | nsus_cif@uhura.cc.rochester.edu supreme being!" | nsus_cif@uordbv.bitnet - Evil (from "Time Bandits") | ... !rochester!ur-cc!nsus_cif
jporter@twaddle.dell.com (Jeff Porter) (02/13/91)
In article <12162@ur-cc.UUCP>, nsus_cif@troi.cc.rochester.edu (Nick Susch) writes: |> |> I assume that the first person is using a Tseng ET4000 board. I also have |> this board and have this annoying flicker problem. I know that 1024x768 |> is interlaced, but the flicker is horible under windows. If I exit |> windows and run a program in 1024 mode, I *can* tell it is interlaced, |> but it is *very* slight, and the screen in very easy to read. But as soon |> as I start up windows in 386 mode, something happens to the card. The |> flicker becomes unbarable. I have discoverd, using the option of my NEC |> 3D which saves the screen setting to each particular sync, that the 1024 |> mode under windows is a different sync then the "regular" 1024 mode. Does |> anyone know why this happens? It's like their is two modes on the ET4000, |> regular interlaced, and really slow interlaced, and windows picks the |> wrong one. Any help would be appreciated. |> It sounds like you've got an especially bad driver 386-mode driver for your VGA card. Jeff Porter
acook@athena.mit.edu (Andrew R Cook) (02/13/91)
In article <15093@uudell.dell.com>, jporter@twaddle.dell.com (Jeff Porter) writes: |> In article <12162@ur-cc.UUCP>, nsus_cif@troi.cc.rochester.edu (Nick Susch) writes: |> |> |> |> I assume that the first person is using a Tseng ET4000 board. I also have |> |> this board and have this annoying flicker problem. I know that 1024x768 |> |> is interlaced, but the flicker is horible under windows. If I exit |> |> windows and run a program in 1024 mode, I *can* tell it is interlaced, |> |> but it is *very* slight, and the screen in very easy to read. But as soon |> |> as I start up windows in 386 mode, something happens to the card. The |> |> flicker becomes unbarable. I have discoverd, using the option of my NEC |> |> 3D which saves the screen setting to each particular sync, that the 1024 |> |> mode under windows is a different sync then the "regular" 1024 mode. Does |> |> anyone know why this happens? It's like their is two modes on the ET4000, |> |> regular interlaced, and really slow interlaced, and windows picks the |> |> wrong one. Any help would be appreciated. |> |> |> |> It sounds like you've got an especially bad driver 386-mode driver for |> your VGA card. |> |> Jeff Porter Just my $.02 : There are two main reasons that you can percieve annoying flicker : The first is the screen refresh rate, as the gentleman noted above. If the windows driver uses the 60Hz mode, you will percieve a noticable 30Hz flicker. If you other program puts the card in a 70Hz (yeah!) mdoe, then you will see considerably less flicker at 35Hz (15% faster refresh). The other reason for the difference in percieved flicker is what you are looking at on the screen. Windows stuff has a lot of horizontal and vertical lines. When the screen is refreshed every other line, Horizontal lines can appear to flicker a lot, especially if they are only 1 pixel wide. Full screen graphics, on the other hand, like gif's, have images that are more uniform. This makes the flicker less percievable. Andy Cook
nsus_cif@troi.cc.rochester.edu (Nick Susch) (02/14/91)
Ok, let me see if I can explain this again, and see if any one can help
me. If I run a 1024x768 mode program *when windows isn't running* it
works fine. When I start windows *in 386 enhanced mode* (at any
resolution for the actual windows desktop screen) and then run the same
program that goes into 1024x768 mode from windows (in full screen mode, of
course) I get an annoying flicker. Its update is *much* slower then 30Hz.
If is more like 5Hz. Trust me, it is that bad! I also (obviosly) get the
problem if I run the windows desktop in 1024x768 mode.
My computer is a 386/25Mhz, with 4Meg ram, and an ET4000 SVGA card. (The
entire card was made at Tseng.) If anyone knows why this is happening,
please let me know, thanks.
"And when I have understanding | /\/ick Susch - University of Rochester
of computers, I will be the | nsus_cif@uhura.cc.rochester.edu
supreme being!" | nsus_cif@uordbv.bitnet
- Evil (from "Time Bandits") | ... !rochester!ur-cc!nsus_cifdan@rna.UUCP (Dan Ts'o) (02/14/91)
In article <1991Feb13.140718.26550@athena.mit.edu> acook@athena.mit.edu (Andrew R Cook) writes:
)The first is the screen refresh rate, as the gentleman noted above. If the
)windows driver uses the 60Hz mode, you will percieve a noticable 30Hz
)flicker. If you other program puts the card in a 70Hz (yeah!) mdoe, then
)you will see considerably less flicker at 35Hz (15% faster refresh). The other
)reason for the difference in percieved flicker is what you are looking at on
)the screen. Windows stuff has a lot of horizontal and vertical lines. When
)the screen is refreshed every other line, Horizontal lines can appear toflicker
)a lot, especially if they are only 1 pixel wide.
I believe the ATI VGA Wonder interlaces at 40-some Hz (i.e. 90-some Hz
interlaced). I've found it to be not too objectionable. Like the article
above says, its worse for images that have many line-by-line changes (1-pixel,
1-line different from the next). Another factor not mentioned is intensity.
Flicker is much worse at high brightness/intensity.
You may find that the ATI card is fast enough to minimize the flicker
that you're experiencing. It would only be a $180 change, rather than replacing
the NEC 3D for a non-interlaced monitor (a very expensive change).
Cheers,
Dan Ts'o 212-570-7671
Dept. Neurobiology dan@rna.rockefeller.edu
Rockefeller Univ. ...phri!rna!dan
1230 York Ave. tso@rockvax.bitnet
NY, NY 10021andreww@uniwa.uwa.oz (Andrew John Williams) (02/14/91)
nsus_cif@troi.cc.rochester.edu (Nick Susch) writes: >Ok, let me see if I can explain this again, and see if any one can help >me. If I run a 1024x768 mode program *when windows isn't running* it >works fine. When I start windows *in 386 enhanced mode* (at any >resolution for the actual windows desktop screen) and then run the same >program that goes into 1024x768 mode from windows (in full screen mode, of >course) I get an annoying flicker. Its update is *much* slower then 30Hz. >If is more like 5Hz. Trust me, it is that bad! I also (obviosly) get the >problem if I run the windows desktop in 1024x768 mode. >My computer is a 386/25Mhz, with 4Meg ram, and an ET4000 SVGA card. (The >entire card was made at Tseng.) If anyone knows why this is happening, >please let me know, thanks. I also have a 386/25 with a Tseng ET4000 card, (but not enough memory to run in enhanced mode :-( ). Firstly, I am pretty sure the Tseng card interlaces at a 47Hz rate or so, not 30 or 60 Hz. I haven't got the specs here, unfortunately (I think it was 98Hz field rate). When I loaded a 1024x768 driver, I got terrible flicker, but this was easily solved by loading one of the other color default color sets in the control panel- I guess the default has an nasty cross-hatch pattern. With the new color set, it is perfectly usable, with only a slight flicker visible on window border lines. >"And when I have understanding | /\/ick Susch - University of Rochester > of computers, I will be the | nsus_cif@uhura.cc.rochester.edu > supreme being!" | nsus_cif@uordbv.bitnet > - Evil (from "Time Bandits") | ... !rochester!ur-cc!nsus_cif Andrew Williams Physics Department, University of Western Australia. (andrew@earwax.uwa.oz.au, OR andreww@uniwa.uwa.oz.au )