ISA video card! One, or two MB video memory!
You bet you'll have problems
Say you use 800x600 as resolution and a color depth of 16 bits
Lets see 800*600*16 is 7680000 i.e about 7.3 MB....
But do you really use an ISA card?
You calculated it wrong. I am not entirely sure does it actually have 2 MB or 1 MB of memory, it has 4 chips (2x2 "grid") an has 2 emtpy "slots", which read "xxx512kxxx". I assume that the 6 chips are 256k each, totalling the capacity to 1MB, and if it had the 2 chips more, the capacity would be 2 MB total.
Remember the difference between BYTE and BIT. One BYTE is 8 BITS, usually. Your equation shows the amount of BITS the 800x600x16 takes, not the amount of actual BYTES it takes. Thus, you need to divide your results by 8 to get the right amount of BYTES. Or then compare that 7.3MBITS against 8MBITS the VGA card has.
Oh, besides I have ran 1280x1024x32 with 4MB card. It shouldn't be possible, but with WindowsXP's default drivers it really was possible. It didn't work flawlessly though, since I got some problems with it, like the some last pixels (which were assigned AFTER the 4MB went full) "streched" the screen from left to right by a small margin, it wasn't really noticeable if it wasn't paid attention.
Well yeah, the problem really WAS the ISA card, as I assumed. Now I got GeForce4 MX 4000 plugged in the AGP-bus and it works flawlessly.
And yes, I really used an ISA card! I need PCI soudcard, but I got 2 ISA cards. ...and I won't plug them in the machine! Never ever more ISA cards for me.
Edit: Oh, the ISA VGA had it's warranty expired over 13 years ago.