I say by accident because high power capacity wasn't a design goal of Starlink, merely a side effect of deploying a communications network.
> My bad. So they're only short like 6 orders of magnitude instead of 9?
No, they're 1 order of magnitude off. (22 MW total capacity of the constellation vs your bar of 100 MW for a single DC.) Again, 3 years ago, using an inferior launch platform, without that even being a design goal.
> What's the latency like?
Starlink latency is quite good, about 30ms round trip for real-world customers on the ground connecting through the constellation to another site on the ground. Sun synchronous orbit would add another ms or two for speed of light delay.
AFAIK nobody outside SpaceX has metrics on intra-satilite latency using the laser links but I have no reason to think it would be materially worse than a direct fiber connection provided the satellites aren't spread out too far. (Starlink sats are very spread out, but you obviously wouldn't do that for a data center.)
Why on earth would you compare their entire fleet to one project? Power generation trivially parallelizes only if you can transmit power between generation sites. Unless they've figure out how to beam power between satellites the appropriate comparison is 6Kw to 100Mw. And again, the generation is the easy side; the heat dissipation absolutely does not parallelize so that also needs to go by 3-5 orders of mag.
And also: radiation. Terrestrial GPUs are going to be substantially more power and heat efficient than space-based ones (as outlined in TFA). All this for what benefits? An additional 1.4x boost in solar power availability? There's simply no way the unit economics of this work out. Satellite communications have fundamental advantages over terrestrial networks if you can get the launch economics right. Orbital DCs have only the solar availability thing; everything else is cheaper and easier on land.
I already gave my thoughts on radiation and economics in my original comment. I agree those could be significant challenges, but ones SpaceX has a plausible path to solving. Starship in particular will be key on the economic side; I find it very unlikely they'll be able to make the math work with just Falcon 9. Even with Starship it might not work out.
And it's not just a 1.4x boost in solar power availability. You also eliminate the need for batteries to maintain power during the night or cloudy days (or cloudy weeks), and the need for ground infrastructure (land, permitting, buildings, fire suppression systems, parking lots, physical security, utility hook-up, etc).