Hi thanks for the recommendation,PCPartPicker Part List
Motherboard: MSI B450 Gaming Plus MAX ATX AM4 Motherboard (£99.02 @ Amazon UK)
Total: £99.02
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2020-05-12 03:27 BST+0100
The Gaming Plus (Max) has the same 4 phase (2x 4C029N Hi Side 2x 4C024N Lo Side per phase) VRM configuration as the Tomahawk. Albeit with different heatsinks. Either should handle a stock 3900/3950x without issue. Many of the MSI b450 and x470 motherboards use the same VRM design as the Tomahawk.Being honest though, if you can afford to throw in another twenty bucks, the B450 Tomahawk or B450 Tomahawk Max are MUCH better choices, with significantly better VRM/Power delivery configurations than the Gaming Plus. If you decide to upgrade to a higher tiered CPU later with the Gaming Plus, you might run into throttling issues. With either of the Tomahawk boards, you could run any CPU all the way up to the 3950x without any trouble at all.
The major airflow vs not recommended disparity is in the OC column for the 3950x. Both get green checks for 3900/3950x stock operation. To my knowledge this spreadsheet is NOT based on actual thermal data. I believe the recommendations are based purely on objective analysis of VRM components and subjective analysis of the heat sinks. Given that these CPU's can't really be cooled (on ambient) while drawing over 150 amps, and overclocking on these CPU's is pretty niche, its probably a distinction without a difference. I find the component data on the spreadsheet much more useful than the recommendations personally.That spreadsheet you linked to specifically states "not recommended" in the column for the 3950x, while the Tomahawk max states "major airflow recommended". Clearly there must be some other differences and it seems odd that the majority of reviewers, like Steve over at GamersNexus hasn't been recommending the Gaming Plus Max if it's as capable as the Tomahawk/Max, in the same way they've gushed over those boards, since it's cheaper.
I do see it lists the same VRM configuration AND the same VRM components, but there has to be something other than just the smaller heatsink to account for the disparity between these boards, unless I'm off my mark somewhere.
Either way though, any of these are more than good enough for the 3600 or 3600x to maintain full profile boost behavior with adequate cooling.