Horun wrote on 2023-12-06, 03:26:

Bit-o-history: XP original public release date October 25, 2001. XP SP3 release date April 21, 2008 (Windows 7 public was Oct. 2009).
First dual channel DDR was the Intel 850 chipset introduced in Nov 2000. Official launch of the Intel 845 was Sept. 2001 which was the first Dual channel DDR for mainstream.
As an example the famous i865 and 875 P4 chipsets were mainstream released in June 2003.

The i850 was RDRAM... (believe me, I had one...)

i845 in 2001 was single-channel SDRAM-only, IIRC. Not sure when a DDR version launched...

I know nVidia had dual-channel on the nForces for Athlon XP around that time, true...

Original Pentium was dual-channel (two 32-bit SIMMs). And 386DX was quad-channel (four 8-bit SIMMs). RDRAM on i850 is also dual-channel - two 16-bit channels.

True the 850 w/Rdram was the first "dual channel". Intel did not allow OEM's by license to use DDR on i845 even though it was capable. Ok will concede my memory was off and the 865 was really first Intel dual channel DDR mainstream in 2003 but there were other like nVidia that had already released dual DDR chipsets. Do know XP was the only desktop OS from MS for at least 6 more years when Dual channel DDR boards were first out 😀

The Serpent Rider wrote on 2023-12-06, 03:39:

Original Pentium was dual-channel (two 32-bit SIMMs). And 386DX was quad-channel (four 8-bit SIMMs). RDRAM on i850 is also dual-channel - two 16-bit channels.

Channels normally refer to bank interleave. The 386DX had 32-bit memory, so four 8-bit SIMMS = 1 channel/bank. 386sx's with eight 8-bit SIMMS were quad-channel though.