CPU of the Week – New Pentium 90 Retail Boxed

Welcome to this, the first in a series of posts about vintage CPUs that I’ve encountered and collected over the years into our museum. We have more than 1200 CPUs, some of which are extremely rare. We will share information and photos of some of these in the coming months.

The above is an unused example of a retail boxed Socket 5 Pentium P90 vintage CPU. Introduced in March 1995, these processors represented the first step after the Socket 4 P60 and P66. They introduced the disconnection of the core motherboard clock (in this case 50, 60 or 66Mhz) and the actual CPU (75, 90, 100 or 120Mhz) in a fusion of the Pentium architecture with the clock doubling and tripling technology of the 486DX2 and DX4.

The motherboard chipset was the 430FX, with no split rail voltage – simply 3.3v all the way. This made the later MMX tech CPUs ‘officially’ incompatible, however there existed overlay devices to allow later (up to 400Mhz) super socket 7 CPUs like the AMD K6III to work.