Upgrading Lab - timing and monitors

Our lab is currently running G3 Macintosh computers with a 2 monitor setup and HyperCard with XCMDs for our programming language. We are upgrading to new computers this spring and are looking into our options with Intel Macs and SuperLab.

My question is in regards to video adaptors and their impact on timing with SuperLab. We would be looking at upgrading to either an iMac or MacPro. In order to reduce our costs, we were hoping to keep our CRT monitors, but with the new DVI technology this would require adaptors to convert DVI to VGA. Would these adaptors impact timing of visual presentations at all?

Thank you for your time,


DVI to VGA adapters will have absolutely no impact on timing. The adapters do not actually convert signals. They are dependent on DVI-I ports, which are DVI ports that output both digital and analog signals. If anything, this will improve timing, as all CRTs provide refresh information to the host computer, whereas not all LCDs do. Specifically, none of Apple’s LCDs do (so far as I’ve found with internal and external). In addition, LCDs rarely have refresh rates higher than 60Hz, while CRTs can easily provide refresh rates in excess of 100Hz at lower resolutions.

Thank you so much for this information!

I’m sorry it took so long to reply. We’ve been very focused on getting the SuperLab 4.0.6 update out.

One feature that I don’t believe is documented anywhere other than these forums is SuperLab’s verbose mode. It’s basically information for debugging experiments. It’s not user friendly, but it includes excessive timing information–including information on when SuperLab is waiting for the monitor and when it has no information. There’s some information here, but if you just search the forums for the word “verbose,” you’ll probably find everywhere that it has been brought up.