The 68040 offered the same features as the Intel 80486, but on a clock-for-clock basis could significantly outperform the Intel chip in integer and floating point instructions. However, the 80486 had the ability to be clocked significantly faster without suffering from overheating problems. In late 1991, as the higher-end Macintosh desktop lineup transitioned to the '040, Apple was unable to offer the newer processor in their top-of-the-line PowerBooks until early 1994. With PowerBooks being restricted to 68030s for several years, "Macworld" reviewers conceded that the best choice for power users was the PC-compatible Texas Instruments 80486 notebook, rather than the top-of-the-line PowerBook 180.