Intel ( INTC)filed a counterclaim against chipmaker Transmeta ( TMTA) in Delaware District Court Tuesday. The move comes a few months after Transmeta, a once-promising semiconductor start-up, sued Intel for infringing 11 of its patents and asked the court to prevent Intel from selling several of its most popular chips, sending Transmeta's shares up by more than 15% in one day. According to Transmeta's claim, Intel's Core 2 and several flavors of the Pentium microprocessors make use of Transmeta's intellectual property covering computer architecture and power-efficiency technologies. Transmeta began its life in the mid-1990s making low-power chips for mobile devices based on the x86 instruction set used by Intel processors. During the past few years, Transmeta has changed its business model, focusing instead on licensing its intellectual property to other chipmakers and providing engineering and designing services. In its response to Transmeta's suit, Intel denies that it infringes on any of the patents and contends that Transmeta has infringed seven Intel patents, some also relating to low-power processor technology. Intel said it is owed triple the compensatory damages because it contends Transmeta willfully infringed its patents. Shares of Intel finished Wednesday's regular session up 2.3%, or 49 cents, to $21.52. Transmeta closed down 6 cents to $1.03.