Talk:RAMDAC
 | This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later. |
 | This article is rated Start-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||
| ||||||||||||||||||||||||
A faster RAMDAC allows for a faster refresh rate? -- Frap 09:44, 8 November 2006 (UTC)
- yes, the faster the ramdac, the faster the possible refresh rate, and the bigger the possible resolution. In newer than a few years PCs the Ramdac is fast enough for really all purpose. 87.234.229.209 19:08, 30 November 2006 (UTC)
- What is the upper limit of a 400 MHz ramdac? If you use DVI, it still use ramdac?
- The upper limit is 2048x1536 analog (at 88Hz in Win XP when using default sync-settings) and 2560x1600 digital (when using dual-link DVI). --MrBurns (talk) 03:52, 5 October 2008 (UTC)
- What is the upper limit of a 400 MHz ramdac? If you use DVI, it still use ramdac?
What's the formula?
editHow is the MHz rating for the RAMDAC calculated? I thought it was H x W x Hz x bit-depth, but that's not right. ---Ransom (--208.25.0.2 20:55, 8 February 2007 (UTC))
- Actually color depth has nothing to do with the (analogue) bandwidth rating of the RAMDAC. It's more like H (plus blanking clocks) x W (plus blanking clocks) x Hz x 2. Zac67 (talk) 22:02, 5 December 2007 (UTC)
- PS: got that mixed up with the sampling theorem - cut the "x 2" part above. Zac67 (talk) 21:39, 29 December 2007 (UTC)
- Add formula to article. -- Frap (talk) 14:33, 6 December 2007 (UTC)
Display calibration, look-up tables
editI was under the impression that the (C)LUT (look-up table) in the RAMDAC is used today for display calibration.
Display calibration can range from simple, fairly mainstream software calibration routines like Adobe Gamma, to hardware solutions used mainly by photographers and designers. Since every computer display (and I mean every unique unit shipped) has a certain deviation from an ideal colour balance, display calibration involves measuring (profiling) this deviation when displaying known coloured patches, and using the measured values to compensate. This allows for a decent match between displays.
The actual compensating is done by placing the correct values in the video card's LUT (look-up table).
I'm not sure whether the LUT I just mentioned is indeed part of the RAMDAC, but if it is, the following section (and possibly other sections) of the article will need modification:
- The SRAM can usually be bypassed and the DACs can be fed directly by display data, for Truecolor modes. In fact this has become very much the normal mode of operation of a RAMDAC since the mid-1990s, so the programmable palette is mostly retained only as a legacy feature to ensure compatibility with old software. In many newer graphics cards, the RAMDAC can be clocked much faster in true color modes, when the SRAM is not used.