Online 7.12 SCO System V Performance Problem

Hy there, we experience a severe problem with Informix Dynamic Server 7.12 on SCO Open Server Enterprise System V running on Siemens Nixdorf 350 (Pentium 133, Adaptec 2940, Quantum 2GB, 64MB RAM). We have three chunks, one with 100MB as dbroot and two with 250MB for the Database and tempfiles. The Database is less than 200MB (we are still testing). Shared Memory ist set to 40MB on SCO's side where >4MB are used by Informix. The problem is: When we start Informix and try a select like select count (*) from artikel where artikel_preis is 39.95we get the correct answer 7350 within 20 seconds. Then we start a level 0 archiv which lasts for 5 - 6 hours (200MB mind you!) and start the select a second time which needs 5 minutes then. Profile shows one (!) read Block per second, u386mon shows 32 Bytes read every two seconds and Cache hits 100% (!). We have no problems with the working Database on SCO Open Server Enterprise 4.2 and Informix 7.10 on a HP Netserver LM 5/90 with 64MB and DPT Level 5 Diskarray and 8 Gig Database! Any sugestions? Thanks in Advance Volker Hett hett@hss.nord.de