How do I lower the pixel clock?

[monette]

I need to lower the pixel clock on a matrox G550 PCI card. I need a refresh rate of 1Hz and at the very maximum 1.5Hz. I have tried using PowerStrip and other tweaking programs but I can't get this low. Anyone have any ideas?

[Paleo Pete]

Anything under 60 will visibly flicker, trying to get it down to 1Hz is probably futile. The refresh rate is hte number of times per second the video card redraws the screen. 60Hz refresh rate redraws the screen 60 times per second. 1Hz would make the computer practially unusable. You would have to wait to see where the mouse pointer is until it refreshes. Wait for it to refresh before you can see any letters you type. I probably would be able to type the entire word "refresh" before any of the letters appeared onscreen. That would be bvery disconcerting.

Why are you trying to get the refresh rate that low to begin with? I think it would make the computer unusable or close to it...Depending on your system and video card the usual refresh rates for most machines stay in the 60-72 range. Anything below 55 or 60 and you'll see the screen flicker or blink, anything under 30 will result in jerky mouse pointer motion. (movies are usually 32 frames per second, most video applications use 30 frames per second or higher to get smooth motion.)

[jcnoernberg]

what is the reasoning for such a low refresh rate? if we know, maybe we can suggest another option.

[monette]

The reason is that I'm trying to run a scanner system with galvanometers. The maximum speed of the galvos is 1.6KHz. Hence with resolution of 2048x1536 where the pixel clock goes to a minimum of 10MHz gives 3.18Hz refresh rate, but this grows to around 4Hz. And the galvos at 1.6KHz with around 512 lines gives 1600/512 = 3.125Hz. But to be on the safe side 1Hz would be ideal.

[saphalline]

First of all, the term "pixel clock" is usually used to refer to the vid chip's core clock speed or GPU/VPU clock speed. This speed has nothing to do with the refresh rate. The refresh rate is set dynamically, according to certain parameters that are agreed upon by Windows, the video driver, and the monitor. The lowest refresh rate I've ever seen a modern CRT monitor hit is probably 30Hz.

It's technically possible to send signals to a monitor that are outside of its range (ie "range of acceptable values") but I can almost guarantee you that forcing a modern CRT monitor down to a 1Hz vertical refresh rate would kill the tube! You'd get maybe a few days or weeks out of it before it would die. And at that point, I'd be worried about the tube exploding or something. CRT's are extremely dangerous if you run them outside their range. Broken monitors that have been unplugged for up to a decade have still been known to kill people who fiddle with them. I wouldn't recommend it myself, but hey, it's your life.