This card on the VGA museum, which is indeed a TVGA8900C, is a perfect match to the profile photo.
I checked the neighbouring chipsets: The predecessor TVGA8900B and the successors TVGA8900C, CL and D. None of them has a matching PCB at the VGA museum, so the guess "TVGA8900C" seems to be spot on. There are other cards with the "old-style" card-edge feature connector, for example early ET4000 cards, as already mentioned in this thread, but the amount of detail that matches the specific TVGA8900C I linked makes it very unlikely that there is another hit.
I wouldn't talk that negative about the TVGA8900C as CharlieFoxtrott. It is true that Trident was clearly at the low end of the VGA spectrum, and their cards were sold for the price, not for the speed or quality. Nevertheless, the TVGA8900 series is what I would call "2nd generation SVGA", supporting up to 1MB of video RAM and 1024x768 at 256 colors. The TVGA8900 chips got better and faster as the series evolved, and the TVGA8900D is claimed to be at least as fast as an ET4000AX, which is limited by the ISA bus most of the time. They say the 8900CL is "nearly as good as the 8900D", but I am unsure about the 8900C. Still, it will be considerably faster than any 8-bit VGA card (like the original IBM VGA card, which is actually called "PS/2 display adapter"), or 8-bit 1st-generation SVGA cards.
Because 1st-generation SVGA cards used 64k x 4 memory, they had a 32-bit memory bus at the VGA minimum memory size of 256k. 1st-generation cards that supported 512KB of video RAM had 2 banks of 32 bits each. The TVGA8800 is an example for a two-bank 1st generation chip. On the other hand, second-generation SVGA chips use 256k x 4 chips, so you get 32 bit memory bus width only if 1MB is installed. Performance of 2nd-gen chips with less than 1MB of video RAM installed will suffer, and in case of just 256KB video RAM, these cards are degraded to an 8-bit memory bus. Even with the advancement of technology since the design of the original VGA in 1987, they have a hard time providing better performance than the original VGA with its 32-bit memory bus. Installing just 256KB on a TVGA8900C might in fact make it "one of the slowest card available". The photo on the VGA museum I linked shows that card with just two memory chips. That one will be slow. Your card has all eight memory chips populated, so I guess you will have a hard time finding an application that is severely limited by the VGA throughput on that chip if executed on an 8MHz 80286 processor.
You should be able to get acceptable performance even at 800x600 pixels (don't expect fluid full-motion video, though!). At 1024x768 (which is still OK on that card), the CPU will have a hard time keeping up unless only minimal parts of the screen need updating. For games like Prince of Persia or Commander Keen, which are typical games to be played on a 286 processor, the card is more than sufficient.
