A six-month run of accelerating revenue growth among IT vendors that culminated in a seven-year high in March 2008 has come to an end.

The Information Age Index, which tracks the growth of the world’s 200 largest technology companies, dropped by 1.1 percentage points in April 2008, falling to 12.9%.

The last time that the industry started to fall from such heights was, of course, the dot-com crash. Could the peak seen in April 2008 signify the start of a similar, credit crunch-induced downturn in the IT industry?

At this stage, the fundamentals don’t suggest anything so dramatic. There was strong growth from industry bellwethers. Cisco grew its quarterly revenues by 10% to reach $9.8 billion, IBM’s quarterly revenues rose by 11% to reach $24.5 billion, and revenues at EMC jumped 17%.

These results were counterbalanced by negative numbers elsewhere. Networking systems vendor Nortel’s revenues for the first quarter were down 14%, development tools giant Borland saw revenues fall 18%, and server and Java company Sun Microsystems and IT services company Capgemini both reported a 1% fall in quarterly revenues.

Raising many eyebrows was the fact that software giant Microsoft failed to grow revenues at all in the third quarter of its financial year – takings were flat at $14.5 billion.

Revenue growth was also decelerating on the European stage. The European Index, which tracks a 50-company subset drawn from the continent, fell by 0.4 percentage points to 9.4%.

On the European side, German application maker SAP’s quarterly revenue growth of 14% had a positive impact on the regional index, but a poor showing from IT services provider Atos Origin, whose quarterly revenues fell by 1% to $2.1 billion, contributed to an overall slowing of growth.