dionb wrote on 2020-12-02, 22:05:
It would probably do 90% of speed of K6-3 on i430TX with 66MHz FSB, which would be about 80% of speed of K6-3 on 100MHz FSB. So a K6-3 400 would run at about the same speed as a hypothetical K6-3 290MHz. It would be the fastest CPU on this motherboard, but not particularly impressive otherwise.
From my own experience and doing benches with super socket 7 boards and using a AMD K6-III with PowerLeap adapter in my Compaq I think the actual performance loss is much less, if any based on the chipset. From testing a Pentium 100 in terms of VGA speed, the Intel 430FX is actually faster than the SS7 chipsets. See: Socket 5 & 7 Motherboard VGA Benchmark comparison. I know this is not exactly comparable as the CPU speed is only 100mhz, but gives an indication. The performance loss will come from running the system at 66mhz FSB.
The cutoff date all depends on your own preference in terms of resolution and frames per seconds. I normally run my games in 1024x768 in my Compaq using the Voodoo2 in SLI mode and I require good framerate, else I'll just go for a newer machine. You mentioned you had a Pentium III in another post, which would be perfect to transition to when your IBM does not cut it anymore. From my own experience using the Compaq the cutoff date is 1999 with the exception of demanding games such as Quake 3 and to a lesser degree Unreal Tournament. High demanding games from 1998 (Unreal, Half-Life) all run fine. Not all games from that era had the same system requirements as Quake 3. For instance Dungeon Keeper 2 from 1999 is running fine on my Compaq.