Rambus' ex-CEO Geoff Tate has resigned from the company's board of directors following an investigation into stock options.

Tate, Rambus board member and CEO from 1990 to 2005, quit the board after grant discrepancies were noticed. The company's audit committee found that real dates for some stock option grants were different to the recorded ones. The committee responsible for overseeing the stock options at the time had but a single member; Geoff Tate.

To "ensure that there is not even the appearance of a conflict of interest," he resigned from the board shortly after. There is no word yet if criminal charges are being considered, as happened recently with Brocade's ex-CEO and founder Greg Reyes.

It seems a long time since Rambus was flying high, with RAM suppliers being found guilty of violating its patents left, right and centre in a string of long drawn-out legal cases. Since then Rambus' award from competitor Hynix has been judged to be too high, it's been accused of anti-trust behaviour, and now its stock options are under investigation.

Rambus also recently downgraded the role of John Danforth, secretary and general counsel during these lengthy legal cases against the semi-conductor companies, to a senior legal advisor focussing on specific litigation. Robert Kramer is now Rambus’ acting general counsel. A class action case filed in a San Francisco court earlier this month alleges Rambus has breached the Securities and Exchange act. The case named John Danforth and others.

The company is delaying filing its second quarter earnings statement as financial reports since 2003 are unreliable. Its shares have declined around 75 percent from in value this year (to $10.80 from $46.99).