Don’t confuse “Bandwidth” and “pixel clock”, although related they two completely different things. The examples above are talking about “ Pixel clock” not the “Bandwidth” capabilities of the video amp.
Bandwidth is a little complicated and needs some explanation and background in monitor technology.
There are three components that make up the monitors refresh rate. Pixel clock, horizontal scan rate, and the vertical scan rate or “refresh rate”. They are all interrelated.
Monitors draw pixels on the screen one at a time starting in the upper left corner across the screen, then down one line and so on. The time it takes to draw one pixel on the screen is commonly called the video rate, pixel clock or bandwidth. The time it takes to draw one line across the screen is the horizontal scan frequency. Finally the time it takes to draw one complete field “entire screen” is the refresh rate.
Basically, the faster you can draw one pixel on the screen, the faster you can draw a line across the screen, the faster you can refresh the screen.
For more information on Pixel Clock speed for specific resolutions see the following link.
http://www.hut.fi/Misc/Electronics/faq/vga2rgb/calc.html
Almost all monitors on the market today have pixel clock and bandwidth specifications that are sufficient for the resolution the manufacturer recommends. But be careful out there. I see some manufacturers that publish the maximum resolution in BOLD print and the recommended resolution is small print. What they are saying is. Yes the monitor will display at that “BOLD FACE RESOLUTION” however the bandwidth of the monitor is really optimized for the lower “recommended” resolution”.
"Bandwidth" is the range of video frequencies that can be adequately handled by the video amplifier of the monitor, this number can be considerably lower than the pixel clock required for a given timing. The reason for this? The highest fundamental frequency in the analog video signal is one-half the pixel clock, since the fastest thing you can do is to turn alternate pixels on and off. One "on" or "white" pixel followed by one "off" or "black" is required for a full cycle - so the highest fundamental frequency you see is derived from the period of TWO pixels, not one.
There are many ways to measure “Bandwidth” - some relevant, and some not. Without knowing how the manufacturer measured the bandwidth it may not be a very useful specification for comparison purposes.
There is good reason I like Hitachi. In my years of working in the industry I have visited many of the Hitachi factories in Japan, Mexico, Taiwan and China, so I’m very familiar with their Q.A process. I’m also a trained ISO9000 auditor.
I have also been to many third party factories that manufacture the ViewSonic models. I have not visited the Samsung factory in Korea yet, however in my line of business its simply a matter of time.
I cannot find any information on a Samsung model 957MB, you certain that model number is correct? Remember also that newer does not necessarily mean better. I’ll use Hitachi as an example. IMHO the Hitachi CM772 was one of the best 19” monitors ever made. The major reason was the Hitachi CRT. Unfortunately Hitachi shut down CRT factories and now most of the CRT’s used are manufactured by Samsung. Personally I do not feel these CRT’s meet the capabilities of the older Hitachi CRT’s. You may like the high bright modes for games and DVD’s, however high bright defocus text base applications so much that it is unusable.
Odds are the G90F, the CM721F and the Samsung model all use the same CRT. Electronics play a big part in video quality, as does the factory alignment. I really don’t want to make a direct recommendation in this public forum, due to the fact that I’m biased.
Drop me a note at jim@monitorsDirect.com
Jim
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