Just for clarification, the 20's had a particular broadcom chipset and the 21/22/23 used a similar but different one. The one in the 20's had faster memory access times and made the 20's faster than any model until the 24's. How fast depended on what you were doing, but 10-15% isnt an unreasonable number. The chipset used in the 21/22/23 was cheaper.
The chipset in the 24's is a completely different vendor and architecture, but its at least 50% faster than the broadcoms in the earlier HR's.
This discussion is similar to many I've had where you have people who are very light users of the dvr who swear it has no problems and isnt slow, and heavy users of the dvr who have lots of problems and hate the slow, inconsistent user interface. IIRC, Jimbo has something like a handful of series links, watches a lot of live tv, and rarely fills up much of his disk. He's a lot less likely to have problems than I do where I have two boxes with 50 SL's each including autorecord wishlists, do MRV constantly, almost never watch live tv, and have a pair of >1TB drives that are at least 50-75% full all the time.
Someone who drives ~3 miles a day to the corner store and back will have a different driving experience from someone who puts in 300 miles a day on the autobahn. Its just that simple.
Usually at this point in the strawman debates, someone will call me out for watching tv too much or overusing the dvr even though that has nothing to do with the discussion. It makes for a nice diversion from the facts.
In the case of this topic, the longer I think about it the more amusing it gets. "Our system wont let you get the product that actually works properly, so quit asking for it and go piss off!". Pretty humorous when you get right down to it. I'd like to see the energy channeled into "How can we get the good product into the hands of the customers who want it?".
Its a case where the customer has become a barely necessary evil that shouldnt cause any more problems for the service provider than necessary.