https://en.wikipedia.org/wiki/PCI_Expresshttps://en.wikipedia.org/wiki/PCI_Express#History_and_revisionspci-e v1.0 = 2003 (introduced) - became commonplace around the end of 2005
pci-e v2.0 = 2007 (introduced) - became commercially available in spring 2008
pci-e v3.0 = 2010 (introduced) - became available in summer of 2011


introductionso these dates are reflecting when the technology was first introduced.. which would have taken time to "trickle down" to the regular commonplace motherboards everyday people were actually buying + using
i wish i had more exact data (ie: month rather than year or actual dates) it probably took a few months for these things to be incorporated in the new motherboard designs.. so as a result pcie v2.0 capable motherboards may have shown up in late 2007, or early-mid 2008, or even late 2008.. depending entirely upon the motherboard companies when they release the new boards etc
pcie v1.0for example the first pci-express capable motherboards started showing up right late in the year
in (Dec 2004) according to this post:
http://www.tomshardware.com/forum/128421-28-first-express-motherboards-availablewhich means that they didnt become common place untill probably mid-2005.
"First PCI Express Graphics Cards Arrive" (Aug 2004)
https://www.pcworld.com/article/117070/article.html
pcie v2.0the first pci-e 2.0 capable motherboards:
"The second generation of PCI Express was introduced with Intel’s X38 enthusiast chipset, and is being carried on by Intel’s X48, AMD’s 790/770 family and Nvidia’s nForce 7 series."
https://www.tomshardware.com/reviews/pci-express-2.0,1915.html
Intel's first PCIe 2.0 capable chipset was the X38 and boards began to ship from various vendors (Abit, Asus, Gigabyte) as of October 21, 2007. (Oct 2007)
(chipsets like G41, P43 Excluded the pci-e 2.0 support! BOOO!!)
if you wanted pci-e v2.0 support you had to get a board that supported the other Eaglelake chispets: P45, G43, G45, Q43, Q45 but some motherboard manufacturers managed to add pci-e to some P43 motherboards.
these were the first to support pci-e v2.0 for Intel!!!!!!)
on AMD platform the 700 series 760G, 770, 780V, 780G, 785G were first to include pcie-v2.0
***all the intel chipset motherboards from the 1156 + 1155 sockets feature pci-e v2.0 support***
**sata 6gb/s was added in sandy/ivy bridge 1155 socket motherboards**
AMD started supporting PCIe 2.0 with its AMD 700 chipset series and nVidia started with the MCP72.[41] All of Intel's prior chipsets, including the Intel P35 chipset, supported PCIe 1.1 or 1.0a.[42]
Like 1.x, PCIe 2.0 uses an 8b/10b encoding scheme, therefore delivering, per-lane, an effective 4 Gbit/s max transfer rate from its 5 GT/s raw data rate.
the first pci-e 2.0 capable graphics card was the Geforce GT 8800 according to this post:
https://www.anandtech.com/show/2365/4 and was released at the end of (Oct 2007).
pcie v3.0the first pci-e 3.0 capable motherboard was introduced by MSI in July 2011 according to this post:
https://newatlas.com/msi-z68a-gd80-g3-motherboard/19158/from what i can see, it looks like pci-e v3.0 first started showing up in intel motherboards that use the LGA 1151 socket in September of 2015 - even tho the technology was introduced in 2010? that seems kind of strange.
here is a page that lists all the pci-e 3.0 capable motherboards released by Asus in 2011
https://event.asus.com/2011/mb/PCIe3_Ready/http://www.10stripe.com/featured/quick/pci-express-2-0.php