From Microprocessor Report:

May 1, 1991 - At an April 9 press conference in New York City, the seeds of change for the perosnal computer industry were sown. The Advanced Computing Environment (ACE) is potentially the most significant development in the personal computer business since the introduction of the Macintosh..

The success of [ACE] depends, to some degree, on how well the 586 [Pentium] compares to the R4000 in price and performance. If ... the 586 arrives late or falls significantly short in performance, as RISC advocates expect, [ACE] machines will be poised to become the most significant new personal computing platform for the 1990s.

Ace never lived up to its initial billing, due in part to a clever response by Intel:

November 18, 1992 - In response to the RISC threat from ACE, Intel accelerated its P5 [Pentium] program and began showing up at every PC industry conference touting the P5 as being only a few months behind the R4000 and offering higher performance. ... As a result, the ACE effort collapsed, and the P5 - still a paper tiger - appeared to have triumphed.

In the meantime however ... the P5 is turning out to be not a few months behind the R4000, but over a year later - and by the time the P5 is shipping, the [R4400] will be shipping with perhaps 50% better performance than the P5. Intel's pre-emptive strike against the ACE initiative turns out to be, at best, wishful thinking, and at worst, a fraud.