Cray Research Inc yesterday added four new supercomputer configurations, including the expected first single-processor models of the X-MP, which give it its cheapest entry-level machine yet, at $2.5m for a 4Mword system; with 16M-words, the single processor X-MP is $8.5m, and either can be upgraded to the existing dual-procesor X-MP. The company has also come up with two and four processor configurations of its top-end Cray-2, each coming with 128Mwords of memory, and priced at $12m and $14m respectively.