> This implies to me that you believed that the primary reason Unicode is slower ASCII is because it takes twice as much space, which I hope you agree is an absurdly out-of-whack statement, no?
Actually, this precise argument comes up a lot in the debate of UTF-16 vs UTF-8 encodings, and is genuinely a valid point of discussion. When you're transferring gigabytes per second out of a web server farm, through a console pipeline, or into a kernel API call, a factor of two is... a factor of two. Conversely, for some East Asian locales, UTF-16 is more efficient, and for them using UTF-8 is measurably worse.
The point is that any decent text renderer will cache glyphs into buffers / textures, so once a character has appeared on a screen, additional frames with the same outline present will render almost exactly as fast as in the good old days with bitmap fonts.
Not to mention that Microsoft introduced TrueType in 1992 and OpenType in 1997! These are Windows 3.1 era capabilities, not some magic new thing that has only existed for the last few years.
None of this matters in the grand scheme of things. A factor of two here or there is actually not that big a deal these days. Similarly, rendering a 10x20 pixel representation of maybe a few dozen vector lines is also a largely solved problem and can be done at ludicrous resolutions and framerates by even low-end GPUs.
The fact of the matter is that Casey got about three orders of magnitude more performance than the Windows Console team in two orders of magnitude less time.
Arguing about font capabilities or unicode or whatever is beside the point because his implementation was more Unicode and i18n compliant than the slow implementation!
This always happens with anything to do with performance. Excuses, excuses, and more excuses to try and explain away why a 1,000x faster piece of hardware runs at 1/10th of the effective speed for software that isn't actually that much more capable. Sometimes less.
PS: Back around 2010, my standard test of remote virtual desktop technology (e.g.: Citrix or Microsoft RDP) was to ctrl-scroll a WikiPedia page to zoom text smoothly through various sizes. This forces a glyph cache invalidation and Wiki especially has superscripts and mixed colours, making this even harder. I would typically get about 5-10 fps over a WAN link that at the time was typically 2 Mbps. This is rendered in CPU only(!) on a server, compressed, sent down TCP, decompressed, and then rendered by a fanless thin terminal that cost $200. The Microsoft devs are arguing that it's impossible to do 1/5th of this performance on a gaming GPU more than a decade later. Wat?