VLB cards can be somewhat tricky, first it matters which slot you use. If there's more than one try the closest to CPU and then the farthest. There might be jumpers on mobo and/or the card that need setting properly (especially if the CPU bus clock is higher than 33MHz). And then there are some really simple but annoying issues like dirty or bent slot contacts, power delivery with too much noise (bad caps in PSU), etc.

If nothing helps do try downgrading the CPU clock to 25MHz to see if that helps or not, if it does then the card should be OK, you just have stability issues.

I don't remember the VLB config but might it have something to do with the zero wait state or more set on the vga jumpers? I remember some Cirrus cards of that generation (up the GD5429) to have such choice at least in the ISA config.

Yes, might need wait states set or the <33, >33 jumper set to over 33, even on 33Mhz bus or lower if it's arguing with the VLB I/O card. Also check if anything is trying to use IRQ 2 or 9 if the card has an IRQ9 enable jumper set.

Thank you all for the responses.

I have tinkered with the jumpers, removed all memories(managed to damage one thing with it a bit, hopefully nothing severe) and then noticed that once the display said "signal out of range" when it froze so i brought other, smaller one from basement and it works with that one.. For some reason the isa trident that was there before had no issue with the bigger screen...
This really caught me off guard..