The consortium was announced on the 9th of April 1991 by Compaq, Microsoft, MIPS Computer Systems, Digital Equipment Corporation (DEC), and the Santa Cruz Operation (SCO).
[9] DEC used the initiative as an attempt to take market share away from the workstation leader, Sun Microsystems, to respond to gains by Hewlett-Packard and IBM,[10] and to proliferate its own technologies.
Compaq, Microsoft and SCO were perceived to be using it as a defensive strategy to prevent "Sun taking over the desktop and replacing Intel-architecture PCs with RISC, Unix SparcStations" with the consequent loss of opportunities for those companies.
[12] Even prior to the announcement of the initiative, a number of companies headed by Compaq and including Siemens, Sony, Silicon Graphics, Unisys and Control Data Corporation favoured the adoption of Unix System V Release 4 (SVR4) as the means to provide portability between the MIPS and Intel architectures.
[15] The emerging rift within the ACE consortium was averted when it was decided to add support for SVR4 alongside OSF/1, thus placating the group which, by then, included Siemens, Sony, NEC, Prime Computer, Olivetti, Tandem and Pyramid among its members.
The upstart platforms did not offer enough performance improvement from the incumbent PC and there were major cost disadvantages of such systems due to the low volume production.
[citation needed] Compaq was the first company to leave the consortium, stating that with the departure of CEO Rod Canion, one of the primary backers behind the formation of ACE, they were shifting priorities away from higher-end systems.
[17] Other factors included Compaq's ongoing restructuring amidst disappointing financial results, the accelerated introduction of the Pentium, and increasing availability of Unix software for the Intel architecture.
[20] Meanwhile, the accelerated delivery and anticipated performance improvements of Intel's upcoming Pentium processor, combined with more competitive pricing, made the "20 to 30 percent premium" of MIPS-based systems less attractive to vendors such as Compaq and their customers.
Intel's response was to accelerate the delivery of the Pentium and to pursue parallel development of three generations of future products (P5, P6 and P7), thus providing a roadmap that could dissuade its customers from adopting RISC architectures.