page_title: Pentium FDIV bug
hierarchical_section_title: Pentium FDIV bug
caption_attribution_description: English: CPU Intel Pentium A80501 with GoldCap, 66 MHz, Vcore = 5V, SX837 = with FDIV-Bug
context_page_description: The Pentium FDIV bug is a hardware bug affecting the floating point unit of the early Intel Pentium processors. Because of the bug, the processor might return incorrect binary floating point results when dividing a number. The bug was discovered in 1994 by Professor Thomas R. Nicely at Lynchburg College. Intel attributed the error to missing entries in the lookup table used by the floating-point division circuitry.
  The severity of the FDIV bug is debated. Though rarely encountered by most users, both the flaw and Intel's initial handling of the matter were heavily criticized by the tech community.
  In December 1994, Intel recalled the defective processors. In January 1995, Intel announced "a pre-tax charge of $475 million against earnings, ostensibly the total cost associated with replacement of the flawed processors." This is equivalent to $730 million in 2018.
context_section_description: The Pentium FDIV bug is a hardware bug affecting the floating point unit (FPU) of the early Intel Pentium processors. Because of the bug, the processor might return incorrect binary floating point results when dividing a number. The bug was discovered in 1994 by Professor Thomas R. Nicely at Lynchburg College. Intel attributed the error to missing entries in the lookup table used by the floating-point division circuitry.
  The severity of the FDIV bug is debated. Though rarely encountered by most users (Byte magazine estimated that 1 in 9 billion floating point divides with random parameters would produce inaccurate results), both the flaw and Intel's initial handling of the matter were heavily criticized by the tech community.  
  In December 1994, Intel recalled the defective processors. In January 1995, Intel announced "a pre-tax charge of $475 million against earnings, ostensibly the total cost associated with replacement of the flawed processors." This is equivalent to $730 million in 2018.
caption: 66 MHz Intel Pentium (sSpec=SX837) with the FDIV bug
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