The technology group at Commonwealth Bank of Australia is becoming "a real engine of growth" for the bank, according to chief information officer Michael Harte.Having delivered $300 million worth of savings over the last three years as the bank's technology was overhauled, the IT group is now in an investment phase and poised to contribute to future growth.In the interim results pack, released yesterday, CBA noted it had spent more than $1 billion over the last 12 months "in a range of initiatives to enhance customer experience and drive further process and productivity improvements.  The group's largest single investment, the four-year core banking modernisation, remains on schedule at its half way stage and will achieve a number of key milestones this year including migration of all deposit and transaction accounts to the new system."According to Harte "a transformation has taken place" over the last three years. The IT overhaul, and $720 million core systems program, have generated new levels of operational agility and resilience for the bank, according to Harte."Sure we had outages but three to four years ago we had 60 or more outages of magnitude on an annual basis. In the year to date we have had five."Last year when the bank was mauled by several embarrassing Netbank outages it suffered 66 serious outages, compared to five in the six months to the end of December.This comes as the bank is stepping up its product enhancement programme. Harte claimed yesterday that the bank is now able to make 1000 to 2000 changes a month to its production environment (customer facing systems) compared to the 400 to 500 changes a month it could manage a year ago.Harte joined the bank almost four years ago, kicking off the core revamp in May 2008. Initially a $580 million programme, that has since grown to $730 million in order to extend the core systems to ASB and BankWest.CBA has partnered with German software company SAP and systems integrator Accenture on the project. Harte said yesterday that the bank was on track to complete the revamp by 2011. BankWest and ASB will migrate to the new system after that.Harte said that some of the new modules in the core systems were bearing fruit already. The real time deposits module and the information systems which have led to a reduction in loan approval times - from 14 days in June 2006 to just five by December 2009 - had helped the bank grow market share.Having reduced the IT expenses from 19 per cent of bank expenses to 13 per cent over the last three and a half years, Harte has yet to achieve his stated ambition of reaching 11 per cent."The underlying IT expenses have gone down, but IT investment has gone up," he explained. And Harte stressed that expenses cuts have not come as a result of jobs lost as the bank currently has 2300 IT staff (6000 in operations and technology) and is "hiring more every day".Although Harte acknowledged that "We are