Am I correct in assuming that I need only find a higher clocked RAMDAC with the same pin configuration as my existing 80 MHz RAMDAC to achieve 1024x768x64k? It should not be too difficult for me to replace the existing RAMDAC with a socket.

I wouldn't be so sure about that. You may also have to modify the clock generator to boost the frequency. Who knows, something might also be hard coded into the BIOS about which RAMDAC the card is equipped with. I've never tried it before, but it would be an interesting experiment. Maybe you can try seeing if your RAMDAC will overclock first before slicing it off and soldering on a socket.

FGB wrote:

Anonymous Coward wrote:

I have seen 8-bit and 16-bit RAMDACs. What is the difference if they both operate at the same speed?

Also, I believe the MicroLabs card DOES support 1024x768 at 64k colours, but only in interlaced mode.

The difference is the color depth: 8-Bit means the DAC is capable of 256 colours, 15-Bit 32768, 16-Bit 65536 and 24-Bit 16 Million colours.

This sort of begs the question of why modern video cards try for 32-bit true color when oftentimes the monitors are only capable of 24-bit.

Very interesting stuff here, will have to hold onto it for when I start getting 286/386 systems together.

Sedrosken wrote:

FGB wrote:

Anonymous Coward wrote:

I have seen 8-bit and 16-bit RAMDACs. What is the difference if they both operate at the same speed?

Also, I believe the MicroLabs card DOES support 1024x768 at 64k colours, but only in interlaced mode.

The difference is the color depth: 8-Bit means the DAC is capable of 256 colours, 15-Bit 32768, 16-Bit 65536 and 24-Bit 16 Million colours.

This sort of begs the question of why modern video cards try for 32-bit true color when oftentimes the monitors are only capable of 24-bit.

Very interesting stuff here, will have to hold onto it for when I start getting 286/386 systems together.

CRTs have infinite color depht... Not that it matters even on LCD, as 24 and 32 bits color depht are the exact same thing as far as the number of colors they can represent: on 32-bit modes the highest byte (alpha) is ignored, and sometimes used for transparency in image files. The extra byte is just so that the pixels are QWORD aligned (and thus faster to address and manipulate)

Then that explains why a good CRT has always been better for color reproduction for me than any LCD monitor I have. Even the Ultrasharps pale in comparison to a good old NEC Multisync.

hello !!
my machine is a
COMPAQ PROLINEA 4/66
486dx2/66mhz
16 mo ram
hhd 3 go
the video card integrated to the motherboard is a tseng ET/4000W32 and 1mo ram
im running WINDOWS 95 and ive got just only to the maximum possibility 256 color
i want 16 million color but when reboot its not possible
its ok or not ? please help me

Providing that the graphics card itself has no problems in supporting hi/true color modes, as far as know, with 1mb video RAM, 16.7 million colors (true color) is only possible at 640x480 resolution. If you want it at higher resolutions like 800x600 and 1024x768, you need to have 2MB or more video RAM on your graphics adapter. I might be wrong, but this is what I remember from the days long past.

At 1024x768 you actually need more than 2MB.

yamnaka:
If you're lucky your W32 has support for 15/16 bit color. I pretty much doubt for 24 bit support.

It should do 640x480x24bit, but it will be slow. Bet to stick with 64k colour.

Hi elianda,

it's interesting that the ET4000/W32p on my D882 (SNI-PCD4L) also shows no picture within Win95 and the correct monitor-setting (60hz).
It seems that I need to load vmode as you mentioned before.

Thx!

FGB wrote:

Anonymous Coward wrote:

I have seen 8-bit and 16-bit RAMDACs. What is the difference if they both operate at the same speed?

Also, I believe the MicroLabs card DOES support 1024x768 at 64k colours, but only in interlaced mode.

The difference is the color depth: 8-Bit means the DAC is capable of 256 colours, 15-Bit 32768, 16-Bit 65536 and 24-Bit 16 Million colours.

There are usually two important bit widths. One is the bit width for the color output and one is the bit width for memory access.
Typically the older DIL DACs have 8 bit memory access and palettized 8 bit color width (256c). The later small squared surface mounted DACs mostly have 16 bit memory access and up to 24 bit color width. (like the AT&T ATT20C498-13 135 MHz)
This always goes in hand with the clock (max. pixel frequency) and memory amount. It doesn't make sense to have 4 MB graphics RAM a DAC that can do 24 bit color but only has a 8 bit memory interface. The memory interface would severely limit the available modes.

elianda wrote:

The later small squared surface mounted DACs mostly have 16 bit memory access and up to 24 bit color width. (like the AT&T ATT20C498-13 135 MHz)

I disagree. From what I have seen, 8-bit was still the most common variant in surface mount form.

Ok, I might have no actual significant statistical overview about how common specific DACs were. So it was more speculation. I may also have my focus a bit more on the higher end cards.