Siran wrote on 2023-07-22, 16:13:
Thanks again for the very detailed explanation! That TVGA 9000B was part of my very first PC as a teenager. Didn't know any better back then and since the monitor was some 14 inch low quality noname as well, I guess I never really realised how bad the PQ was.
If the image quality issues are "jail bars", that is vertical stripes of higher and lower brightness, LCDs are often more sensitive to subtle quality issues than CRT monitors. LCDs digitize the analog video signal without doing any kind of oversampling. They just take one sample per pixel. This makes them prone to aliasing effects, converting high-frequency interference to low frequency brighteness variations. On the other hand, I already saw jailbars on some Trident cards already on a cheap 14" CRT.
Siran wrote on 2023-07-22, 16:13:
The VGA card was part of a budget 386DX-40 build with 4MB RAM, a 120MB Conner (that sadly died after all those years) on a 4386-VC-HD mainboard.
I hope I don't spoil your childhood, by mentioning that these budget computers were not that good at value per budget. These PCs often got awards from the press as "best 386-class machine", and no vendor stops selling a machine that just got an award, even if its technology is obsolete. As the 386 DX-40 was the fastest 386-class processor available, and using 64KB cache (cheap, as the mid-level 486 computers already used the next generation chips providing 256KB) with 80ns RAM (cheap, as the 486-class computers required 70ns RAM) was good enough to deliver decent 386 performance. Nevertheless, a 486SX-25 could outperform a 386DX-40 at many tasks. Getting a 486-class machine with VL graphics definitely outperformed any 386-class machine with ISA graphics.
Siran wrote on 2023-07-22, 16:13:
I remember having a CL VLB card in my old 486DX2-66 that I had after this PC. I only remember that it had small stripy artifacts in certain SVGA games, I believe in the 3D battle scenes from Battle Isle III, so I wasn't that impressed by its quality back then, but now as an ISA card, I quite like it. They almost looked like memory-overclock artifacts (which I didn't) now that I think about it.
CL VLB graphics card were very common, and delivered acceptable performance for their low price. Most of those cards ran the memory with plenty of margin (70ns at 50MHz, 60ns at 57MHz, as described in this thread), but possibly some low-end cards used 80ns memory and an even lower memory clock, except for high-resolution SVGA modes. As the memory clock on those Cirrus chips is software programmable, it's not impossible that the BIOS used a safe MCLK for low-demand modes, but increased it for modes with high demand for memory bandwidth (like 640x480x64K).