It is pretty clear from the abundance of enquiries on Microsoft Answers ever since IE6 on this subject, and the lack of any solution, that this is not a problem Microsoft concerns itself with. The support staff generally come up with useless remedies - like reinstall Windows!
Microsoft considers it normal to have several methods of font smoothing, from the original Adobe Type Manager solutions that were incorporated into early Windows versions, and became (font smoothing) then XP ClearType TM (an old remedy from the Apple II reinvented 20 years later in 1997 by Bill Gates, apparently) and since then the solutions from the Vista stable and the current endeavour to get everything tablet friendly for the Modern UI, meaning a different method for each desktop application.
It may not be good enough for some, but there are also many who either don't consider it a problem, or put up with it, or vote with their feet to Linux or OSX, both of which have fewer complaints.
Joncr - I know you don't have Windows ATM - and it is difficult to offer anything else, despite your detailed descriptions. Your description* does sound like a driver issue though - for the Thinkpad, try
LaptopVideo2Go: NVIDIA & Laptop News It is a notebook with a choice of screens on purchase, I believe you have the high end one. I hope the Windows driver is the right one.
*"lower portions... ...blob of black" either driver or scaling??? Scaling occurs in both height and width - rendering tends to be only at the sides of the glyph, leading to more or less intense downstrokes and line width distortions. Black lines on one side of icons for instance can be due to driver faults.
https://www.grc.com/ct/ctwhat.htm gives an account of SubPixel rendering, and at the bottom of the page, what can go wrong if the order of colours is wrong for an algorithm that renders the font.
It may well be that less accomplished kit does not show the problems as much as cutting edge displays. I have a cheap £250 HP/Compaq 15" 1366x768 notebook built for Windows 7, which displays on all browsers without issue. Differences between them, yes, as my screenshot shows, but without hideous distortion.