Shares of Sun Microsystems surged on Thursday as an analyst firm upgraded the company's stock based on its relationship with AMD.

Sun rose more than 10 percent to $5.51, nearing its 52-week high of $5.64. A note from Banc of America raising Sun to a buy from neutral appeared to be one driver of the uptick.

"Our upgrade is based on longer-term fundamentals, including our belief that Sun's partnership with AMD holds promise and a more bullish outlook on enterprise spending," the analyst firm said in the report.

El Reg broke the news of Sun's love affair with Opteron last year. Sun plans to roll out an entire fleet of Opteron-based systems from workstations to four processor boxes and eventually beyond.

The industry enthusiasm around AMD's Opteron product has sparked more and more speculation that Intel will release a x86-64-bit product of its own.

Sun is approaching $6 per share for the first time in a long while. Last year, the company enjoyed a brief share spike before reporting a large loss that caused investors to run.

Sun is set to report its second quarter earnings next week with analysts expecting a $0.05 loss on sales of $2.71 billion. A couple of firms, however, have said they expect Sun to come in closer to break-even, and our sources suggest Sun may well post a profit. &