My gods. Dude, those things were slow on the very day they CAME OUT.
I don't know why Sun even made the SparcClassic. They were absolute garbage, then you look at how expensive they were and it's even more mind blowing.
It was the low cost SPARCstation LX, which itself was not a screamer, but fast enough.
You have to remember the PCs of the time were mostly i386. This was pre-Pentium, and i486s were still very expensive. All PCs were ISA bus (16-bit at perhaps 20MHz) versus the 32-bit 25MHz SBUS serving the SPARCstations of the time, and it can be seen that anything beyond the CPU was much faster on any SPARCstation. And even CPU wise, SPARC had the legs of even the highest end i486s of the time, especially on FPU performance (though a well cached 486 would probably edge it in integer benchmarks.)
The real SUN competition of the time were HP and the MIPS based vendors, both of whom pummeled SPARC CPU wise, but lagged in areas such as standards and vendor lock in.
If you were doing typical workstation type stuff of the 90's (modeling, simulation, anything FPU intensive) a SPARCstation really was cost effective against the actual competition (MIPS, HP.) Intel workstations just weren't in the game at this time.