What ever happened to Tandem and NonStop OS 2052

Hmm, you are perhaps counting demonstration chips rather than production chips? Or, the "first 64-bit, 1 GHz" designation?

papers on 1 GHz Alpha, PPC, and x86 at ISSCC, February 2000

- B. Benschneider, et al, "A 1GHz Alpha Microprocessor"

An air-cooled Alpha microprocessor with an internal clock interconnect layers and dissipates 65W.

- H. Hofstee, et al., "A 1GHz Single-Issue 64b PowerPC Processor"

A single-issue short-pipe 1GHz PowerPC processor uses 0.22 um (0.12 um L eff), 6-level copper interconnect CMOS. The design uses nearly 100% dynamic circuits and includes 64kB caches, address translation hardware, and dual precision low-latency floating point unit.

- P. Green, "A 1GHz IA-32 Microprocessor Implemented on 0.18 um Technology with Aluminum Interconnect"

A 25M+ transistor 0.18 um CMOS, 6-layer aluminum interconnect processor operates at 1GHz at room temperature. Performance is achieved by a combination of interconnect aspect ratio optimization, low-K dielectric and design timing optimization. Incremental design effort is low compared to the same design with copper interconnect.

1 GHz AMD Athlon systems, announcement dated March 6, 2000

1 GHz Intel PIII systems, announcement dated March 8, 2000

1 GHz Alpha systems, announcement dated July 16, 2001