I've been messing around with SetMul, FSB and caches to experiment with different speeds on my K6-III+. I'm struggling to get a 486DX2-66, though, and was wondering if it just wasn't possible?

External Cache in BIOS always seems to yield some sort of adjustment. Using SetMul's "L2D" command to disable the L2 cache doesn't seem to have any impact on speed or performance at all. L1D seems to have the same effect as disabling both L1D and L2D while L1DX does seem to successfully disable the L1 cache while leaving L2 on as the speed is different.

With the lowest 66FSB and 2x multiplier Phil shows he gets ~386DX-25 with no caches and ~486DX-33 with just the external (motherboard) cache. I think I've tried external off and L1/L2 on and external + L2 on with L1 off and maybe was able to get 42 or 44... I don't recall. I think if I did 100FSB/5.5x and disabled just L1 cache I might have been able to get a little higher -- 49 maybe 50? I'm going by a slowdown utility that tells you what 100% is in terms of 'an X MHZ 486' and also judging based on games that recommend a DX-66.

Has anyone been able to achieve this with any configuration of FSB/Multiplier/Caches? I'm finding many games where it seems like the sweet spot would be a DX-66.