The Celeron 300A was the one most folks would go after for this. I don't recall the exact retail pricing at the time, but they were more or less guaranteed to overclock to 450mhz and be fully stable. Typically retail pricing could be had at discount to the published wholesale pricing within a couple months of release due to how quickly the market moved back then.

These were competing with PII processors in 1998, and for folks who wanted to go dual CPU it was the way to go.

There was a whole cottage industry of folks modding these CPUs as a small side hustle for people who were not comfortable with soldering onto CPU pins if you wanted to put these into a SMP system.

Performance really did mostly scale linearly with clock speed back then - but for a single CPU. The dual CPU setups were not nearly as efficient due to software not being as multi-threaded as it is today. The big win were folks with two monitors (rare!) who could run apps on their second monitor while playing games on the first. Typically you would only see frame-rate increases with CPU clock - and of course the very start of the serious 3D accelerator (3dfx, nvidia, ATI) scene back then.

It was certainly the golden age of enthusiast computing - especially for gaming.