CBA's $1.1 billion core modernisation programme's much vaunted real-time banking capability is now up and running for retail customers, with business clients set to follow suit later this year. But there's a catch: the real-time functionality is only available for intra-CBA transactions. Any transactions involving other banks are still reliant on overnight inter-bank batch processing systems.And, even if customers bank a Commonwealth Bank cheque in their CBA account, although it may show up in their CBA accounts in real-time, the funds won't be available until the cheque is cleared over the usual period.While the system still has these limitations, the real-time relationship banking platform that CBA is mid-way through rolling out does provide the bank  with a significant competitive advantage over its three main rivals in terms of cost and agility.The core modernisation programme has also substantially reduced the number of major systems' failures the bank has to endure.It does still have failures. Witness the ATM collapse a fortnight ago.  However, according to group chief information officer Michael Harte, the number of Severity One failures (basically, a computer failure that has no obvious workaround, which means the system can't be used) has dropped dramatically. He said the rate of "Sev 1s" had dropped 94 per cent, and that while there had been 66 such outages in 2010, there had only been four to date this year.Speaking at a briefing in Sydney yesterday, CBA chief executive Ralph Norris said the core modernisation programme was a key contributor to efficiency and would help the bank achieve a cost-to-income ratio of 35 per cent by 2013. Harte suggested this might be achieved even earlier than 2013 but did not hazard a date.Harte said the CBA had annual infrastructure costs of A$650 million, but these were being shaved by as much as $100 million a year courtesy of the reforms. He said the savings would be split three ways, between the bank's bottom line;  customers, and reinvestment in advanced technologies such as real-time analytics. The latter will give the bank a finer understanding of both its competitive and risk positions.At its half-year results briefing earlier this year, CBA said the core modernisation programme's scope had been extended and would now cost $1.1 billion - representing almost a third of the bank's total investment budget.  Chief financial officer David Craig acknowledged yesterday that: "Implementing something like this is a high risk, long term strategy - you're going to invest a lot of money and take a lot of risk before you see any benefits at all." He said the bank had been "pretty courageous" in terms of its willingness to "take all that risk and cost, and wonder where... [it] will see the benefits after five years."The bank, however, believes it has a two-to-five year head start on its three leading rivals, which have yet to make much headway with their core revamp. In what appeared to be a swipe at other banks' sluggish performance, Norris said that a transformation in banking was underway. In