When I had my standard DirecTV receiver I could blaze through the channels, they would not come in right away, but the channel and show detail bar would come up. The guide was also snappy and I didn't really see it draw. With DirecTV and TiVo I cannot really blast through channels, it lags. It takes about 2 seconds for the show information to pop up. If I chose the channel, it takes another 2 - 3 seconds for the channel to come in, where before it took about 1 second (that's probably TiVo lag as royaldank said).
The guide is almost unusable, it's so sluggish. Paging up and down has to refresh the channel list. There are times when the guide does not repaint for over 10 seconds, then the descriptions start to trickle in. With regular DTV it was not exactly blazing, but never annoyingly slow.
Any ideas?