New Theory - Looking for Thoughts

I don't think so because I have been recording two MPEG4 shows while watching a prerecorded MPEG show all at the same time without any problems. I suggested some days ago that posters should give more information, such as:
Is the issue observed related to MPEG4 local HD channels? Where are the MPEG4 stations located? I get mine from San Francisco and San Jose in California and I don't seem to have most of the issues posted by others. My only issues with MPEG4 redordings have to do with the 30-sec slip and 6-sec back features. But I never get the BSOD nor missing recordings nor blank spots inside recordings. And my HR20 was installed on September 15th.

Have you tried what I described above? Record two MPEG4 shows at the same time while you playback an MPEG4 show recorded previously? How many issues do you observe during, say 30 minutes? I don't observe any issues, so I think it is safe to say that there is a data throuput problem in the HR20. I'll be looking forward to more posts on this thread.

I just saw your post in answer to mine. You are right in what you said about our ignorance of who is manufacturing these boxes and what exact hard drives are being used in them. I don't know whether my hard drive is a 7200 rpm or a 5400 rpm. I also have an Model 10-250 HD Tivo box, and that one does indeed use a 5400-rpm Western Digital drive. And that Tivo box also is capable of recording two MPEG2 programs at the same time while I playback another program recorded previously. Since MPEG2 is less agressive in compressing the video content, I suspect (but am not sure) that disk writing and reading operations may be more demanding than is the case with MPEG4. One thing I noticed while brosing through all the posts at our forum is this: I never see posts with MPEG4 problems in my area, but a lot of posts with those problems in Florida, in Texas, and in some souther states. Could it be that these problems have to do with the source of the MPEG4 local stations? I live in the San Francisco Bay area and don't have any of the problems I read about in the forum. Before the current software update, I used to have problems with FF and slip ahead while playing back recorded shows; but with the new version of the SW, I haven't had any problems. I have posted these thoughts before with the hope of getting confirmation from others who live in my area, but have seen none so far. DTV is using spot beams to transmit local channels back to their areas of origin, and it may be that the subscribers who are having problems with local MPEG4 HD channels might be off the main beam from the sat. Maybe we should compare siognal strength readings for the transponders on the 99- and 103- degree sats.