Most VESA SVGA games will work without LFB support, but will run noticeably slower as a result.

14MB of RAM is probably enough for most late DOS games that will run playably on a 486, although it may be a bit tight for Windows 95 if you run that.

Is it the physical presence of the RAM that causes loss of LFB, or is it when you make it available as XMS/EMS? If it's the latter, then you may be able to set up separate boot profiles to choose between LFB and more RAM.

Thanks, I think I need a few prominent game titles now in order to test the difference between LFB and absence of LFB, to determine how important it is...

in my experience, the CL GD5428 drops LFB support immediately when you install 16MB RAM or more, regardless of available XMS/EMS. I tested this with Univbe 5.2 and 5.3. 😢 BUT if it turns out that LFB-dependant games still run too slow on a 486 DX4 with LFB enabled, and would run slow even on a Pentium with a good AGP card... then the whole issue is irrelevant.

I seem to remember Rebel Assault 2 stressing my 486DX4-120 pretty well, and it ran a lot better with a VLB card than an ISA one.

LFB doesn't have much impact on 486 class machines because the CPU is too slow to keep up at higher resolutions. It is possible to gain a few FPS in low-res/high-color modes, but not many games support these.

On faster CPUs with MTRR's (Pentum Pro/II, K6-2 CXT, etc...), LFB has a lot more impact because the LFB ranges can be cached.

HunterZ, 5u3, thanks!
I have just finished a test run of Rebel Assault 1 and 2 and 7th Guest plus the 11th Hour. As you have pointed out (and I witnessed) that indeed the CPU is too much of a bottleneck in the 1st place. All in all, the GD5428 seems to be a better all-arounder, even with its inferior speed and refresh rate support.