mac mini and elgato external HDD question

[147798]

Late 2009 mini (2.26GHz) with internal 5400RPM drive. I'm using Elgato eyetv one for over-the-air HDTV tuner and recording on the elgato sw.

With the internal drive set as Elgato's working drive, I can both record TV and view a recorded program at the same time.

But, the internal drive is small and I need more storage. One route, of course, is to install a new drive internally.

But I was wondering if I could just add an external to handle the files. This would require (in the above scenario of recording and viewing) lots of data both to and from the drive.

I tried it with a 3.5" 7200RPM with a USB external enclosure. Not good.

Then I tried a 2.5" 5400RPM drive with a FW800 enclosure. Worked almost flawlessly, but there were a couple of dropped frames.

My question -- if I purchased a 2.5" 7200RPM drive over FW800, will it make a difference, or is the bottleneck the FW800?

Any help is appreciated.

 

[spinnerlys]

I doubt that even USB would be the bottleneck as compressed HD footage takes no more than a couple of MB/s if ever.

I think it is the combination of everything, but I can't pin my finger on anything.

2.5" 5400rpm HDDs can have a write and read speed of up to 75MB/s, the 7200rpm will speed that up to 95MB/s.

Unless your HD stream needs more than 75MB/s, which I highly doubt, the 5400rpm drive should be fine, even with USB.

Can you take a look at Activity Monitor and see what process might hog up the CPU and what the Disk Activity is like when you record and watch simultaneously?
Don't forget to select SHOW ALL PROCESSES.

 

[Cave Man]

My question -- if I purchased a 2.5" 7200RPM drive over FW800, will it make a difference, or is the bottleneck the FW800?

The bottleneck is the FW800. But it's really not a bottleneck - or it shouldn't be. FW has its own controller, while USB relies more heavily upon the cpu. That's why it's better.

I doubt that even USB would be the bottleneck as compressed HD footage takes no more than a couple of MB/s if ever.

The problem is that the Eye TV tuner is a USB device and it competes with other USB devices on the bus. That's why FW works much better as an external recording drive than does USB. I had the exact problem the OP had when I was running my HTPC with a Mini and a 3.5" FW400 setup made the problems go away.

 

[147798]

OK. I'm hearing stick with FW (which my tests bore out anyway), but that 5400 or 7200 RPM drive shouldn't make any difference. So, if I've got some stuttering it might be something else.

It's a late 2009 mini (2.26GHz) with the factory-installed 2GB RAM. There's still a whole 1GB available when booted, as I am only running the DVR functionality, so there shouldn't be disk swapping, which could slow everything down. So, unless someone tells me that I have to have 4GB, I think I'll just get a 5400RPM drive and live with it.