Xref: utzoo comp.os.msdos.misc:378 comp.sys.ibm.pc.misc:2269 comp.windows.ms:5878 Path: utzoo!attcan!uunet!wuarchive!udel!rochester!uhura.cc.rochester.edu!ee.rochester.edu!stanojev From: stanojev@ee.rochester.edu (Bob Stanojevich) Newsgroups: comp.os.msdos.misc,comp.sys.ibm.pc.misc,comp.windows.ms Subject: Re: NEC 3D OK in interlaced 1024 x 768 ?? Message-ID: <1990Oct3.144919.26784@ee.rochester.edu> Date: 3 Oct 90 14:49:19 GMT References: <1618@mitisft.Convergent.COM> <1990Sep28.235629.15785@rick.cs.ubc.ca> <5061@hsv3.UUCP> <1990Oct2.152122.25078@ee.rochester.edu> <5099@hsv3.UUCP> Reply-To: stanojev@ee.rochester.edu (Bob Stanojevich) Organization: University of Rochester Department of Electrical Engineering Lines: 54 In article <5099@hsv3.UUCP> jls@headland.UUCP (James Seidman) writes: >In article <1990Oct2.152122.25078@ee.rochester.edu> stanojev@ee.rochester.edu (Bob Stanojevich) writes: >>I am not sure but it seems to me that there is no point to have non-interlaced >>monitor if the pixel clock frequency is smaller them 90Mhz since the >>refresh rate will be below 50Hz-55Hz what is considered minimum for any >>reasonable flicker free non-interlaced display. Many of high end displays >>have 66 - 70 Hz refresh rate and that requires pixel clock of 120 - 150 Mhz >>for megapixel display. > >You certainly don't need clocks that high! As a rough order of magnitude >for clock speeds, you can use this formula: > >(horiz. resolution) * (vert. resolution) * (frame rate) * 1.33 = (pixel clock) Of course everybody knows that formula so lets use it for SUN high res monitor 1600 * 1280 * 60 * 1.33 = 163.43 Mhz so you are talling that "You certainly don't need clocks that high". I was not refering only to the SVGA. The Sony 30" monitor for 2000x2000 pixels has 350 Mhz bandwidth ($30,000 price tag). > >In any case, there's a big advantage to having a 60 Hz non-interlaced display >over an interlaced one at 88 Hz. And this 60 Hz 1024x768 display can be >done at a mere 65 MHz pixel clock. That is the point. I thought the same but what is the "big advantage"? You have not explained that. I used to not even consider interlaced as an option. I got the board-monitor combination mentioned above and was really surprised that the sharpness was excelent and I could not see the flicker. That is why I posted the article because for SVGA resolution I can not see that "big advantage" over interlaced. > >>So far almost all SVGA boards have clocks in the >>range of 40-50 Mhz. I can not see how they can achieve better refresh rate >>then 45-50Hz in non-interlaced mode with that clock speed.. > >I'll strongly disagree with this one. Names that I can come up with off >my head which have greater than 50 MHz clocks on their SVGA boards are >Video-7, Orchid, Everex, Sigma, WDI, and ATI. (Many manufacturers are >missing here, as I said these are off the top of my head.)-- I am not claiming I have seen all the SVGA borads but do you claim from top off you head or you know defacto from the specks? In June this year I know that in SVGA (1024x768) mode nither ATI nor WDI had non-interlaced becuase we were looking to buy one and we could not get. We were told to by Orchid ProDesign if we want non-interlaced board by the resaler. -- ***************************************************************************** * DISCLAIMER: I am entirely responsible for the content of this document, * * however, I am entirely IRRESPONSIBLE for any grammatical and/or spelling * * errors that might be found in this document. *