Intel says the Commission did not have sufficient evidence of any wrongdoing by the company and the case turns on what customers' subjective understanding is.
Intel has appealed the judges European Union General Court in Luxembourg to reverse a €1.06bn ($1.33bn) antitrust fine, claiming that the investigators used profoundly inadequate evidence and erred in their analysis.
A panel of five judges at the General court, Europe's second highest court, will hear arguments from both the EU lawyers and Intel during a four-day hearing.
The case from Intel rival Advanced Micro Devices (AMD) centers around Intel's use of rebates to block smaller rivals violating EU antitrust rules.
In 2009, the European Union regulators imposed the biggest-ever penalty, which represents 4.15% of Intel's 2008 revenues, after they found Intel guilty of anti-trust offences, Reuters reported.
The European Commission (EC), the antitrust arm of the European Union (EU), found in a probe that Intel impeded competition and hurt smaller rivals by offering discounts to PC makers like Hewlett-Packard, Dell, NEC and Lenovo on a condition that they mainly use Intel processors for their systems.
"These kind of rebates can only be intended to tie customers and put competitors in an unfavourable position," European Commission lawyer Nicholas Khan told judges.
Intel can appeal the General court's decision to the highest court, the European Court of Justice.
In 2009, Intel paid $1.25bn to AMD to settle a civil legal dispute in the US, and settled with the US Federal Trade Commission in 2010, agreeing to some anti-competitive practices that can't be used.
Again in February 2012, the company agreed to pay $6.5m to the New York state attorney general to meet certain costs incurred in the litigation.
