Computer Question: Where is the modern PC's bottleneck?

I am building a roll-your-own TiVo clone with PC parts–some people call this type of setup an HTPC (Home Theater Personal Computer). Please do not tell me that this is a stupid idea, and that I should just buy a stock TiVo. I am resigned to my hobby project. Half of the fun is building it myself.

I intend to buy (or salvage) most of my parts from well behind today’s bleeding edge (or from my extensive hardware graveyard), for cost reasons. However, I don’t want to unknowingly introduce a performance bottleneck by purchasing (for example) a 5400RPM hard drive, or a motherboard that only supports ATA-33.

My question(s) then:

  1. What component in a modern PC is most likely to be the bottleneck,
  2. What speed (MB/s or MHz) does that bottleneck limit me to, and
  3. Accepting that limitation, how ancient can my other components be and still measure up?


Hmmm, don’t have much time for a better answer right now, if someone hasn’t been more complete I’ll stop by again.

I did want to mention though that video capturing is a CPU intensive proposition. I’d recommend nothing less than a 1 gig machine. Encoding movies also is CPU intensive, but even a slow CPU can chug along, it’s just going to take you a looong time :wink:

I’m not worried about the time it takes to encode and burn to CD – I’ve already realized that the HDD speed I think want only comes in sizes large enough to hold several hours of video.

I am worried about not having enough CPU power to do the capture, but your recommendation is pretty much in line with what my research turned up, which is that for capture, I’ll want at least 1 GHz.

The motherboards I’m looking at are all no older than three years, since I figure (unless one of you says otherwise) I’ll want a 233MHz bus or faster.

If you want to use the PC as a TiVo, you’ll probably be encoding MPEG video in real time. 1 GHz might not be fast enough if you’re also capturing at the same time, and definitely won’t be enough if you’re using MPEG 2. Perhaps you should look into hardware encoders.

Just answering Q1 here. In approximate order, strictly IMO of course:

1/ bus speed
2/ hard disk speed
3/ CPU speed
4/ amount of CPU cache
5/ amount of RAM
6/ CD drive speed