This EGA card looks like a standard late clone of the IBM EGA card. The only pixel clock generated on that card is 16.257MHz (just as on the IBM card), but like the IBM card, it can also use the 14.318 MHz clock supplied on the ISA bus. It has the two RCA jacks that are not connected to anything on the card itself, but only to the pin header on the top (called the "feature connector") for add-on boards, again just like the original IBM card. The video RAM is 256KB in 8 chips (unlike the IBM card, as these chips were not available when IBM designed their card), which is the same amount as the IBM card has with the optional memory expansion installed.

There is one surprising thing with this EGA card, though: The 2K x 8 SRAM chip just above the BIOS ROM chip. The original IBM EGA card doesn't need a SRAM chip, and 2K x 8 is too small for a font RAM for a "faster text mode" extension. I guess this RAM might be used to assist in CGA/MDA emulation. The original IBM EGA card is not compatible to MDA or CGA card on a hardware programming level, but many clone cards add a combination of hardware and BIOS software to emulate the MDA/CGA registers. It's likely that the extra DIP switch on that card (the original IBM card only has 4 switches) is some kind of enable switch for emulation modes. Most likely (if the card actually does support emulation), there also is a software tool to turn emulation on or off.

mkarcher wrote on 2021-10-31, 13:14:

There is one surprising thing with this EGA card, though: The 2K x 8 SRAM chip just above the BIOS ROM chip.

Yep the SRAM chip is an interesting twist. It's unlikely to be connected to the EGA chipset, so my best guess is that the SRAM is mapped into the video BIOS memory region to allow for loading some kind of emulation routines. There are three PAL chips on the board so plenty of room for the card to contain some special logic for enabling and write protecting the SRAM.

GabrielKnight123 wrote on 2021-10-31, 12:02:

I have Monkey Island 1 EGA but I'm playing it with a VGA card and monitor would there be a difference for better or worse with an EGA card and monitor

There's definitely a difference! Monkey Island uses the 320x200 graphics mode with the fixed 16 colour CGA/EGA palette. On a true EGA monitor, there will be 200 distinct scanlines shown on the screen with reasonably-sized black area between them. On a VGA card, the 200-line graphics modes are implemented using scanline doubling, so the VGA monitor will actually display 400 distinct scanlines (each of the EGA pixels will be made using two scanlines). With a typical 14-15" VGA monitor of the era, displaying 400 scanlines is enough for them to 'merge' together so that you can no longer see the individual scanlines.

You don't actually need an EGA monitor to play Monkey Island using an EGA card -- at 320x200 with 16 colours, the EGA output is 100% compatible with a regular CGA monitor. An EGA monitor is only required for the hi-res 640x350 modes.