The combined HP/Compaq company will have the largest server business in the UK, according to figures from the analyst group International Data Corporation. But IBM will remain the world's largest server provider.
"The merger will give IBM and Sun a run for their money," said Simon Moores, chairman of the Windows Forums.
The merger leaves Sun potentially isolated in offering only a Unix-based platform, while IBM and HP/Compaq can offer cross-platform solutions.
"In a year's time existing Sun customers should look at what the new HP/Compaq company has to offer," said Ovum senior analyst Gary Barnett.
The merged company should be able to buy components and motherboards at higher volume discounts - price-saving that could lead to lower prices for high-end servers, said Barnett.
The combined HP/Compaq organisation could potentially offer Windows on handheld PCs scaling up to clustered Windows servers, with Unix in the high-end data centre, he told CW360.
The merger could also give a lifeline to users of Compaq's NonStop Himalaya servers, which the company acquired when it merged with Tandem. Martha Bennett, the vice-president at Giga Information Group in Europe, said: "HP could do more with the Tandem [NonStop] technology than Compaq."