Okies; I tell ya I had huge problems getting Skype to function for me on my Gentoo box but what I'm going to explain will help greatly on any Linux distro...

Kernel:

Make sure your kernel is configured for low-latency!

if not your sound card will get sound glitches and cut-outs whenever your hard disks read/write to the drive, among other problems. This is found under -> Processor type and features -> Preemption Model(Low Latency Desktop). also "Preempt the kernel lock"!

Also turn off SMP if your using it... this seems to cause higher latency!

Hard disks:

use fast hard disk drives.. you can use hdparm to set flags that speed-up the drive example:
hdparm -c1 -u1 /dev/hda

check your own settings..


Sound card:

Go for a sound card with at least 1 DAC, with no DAC no way are you going to get anything useful out of Skype. I use a CM-Media 8738 this is a very cheap card you can get from ebay for less than $10 and is very well supported in Linux .. full duplex 16bit capture/playback with more than 1 DAC

Read the documention that comes with your sound card driver in the Kernel source ... sometimes they tell you stuff that is VERY useful in order to get the best out of the device.

Also!! try to configure your BIOS if possible to get the sound device on IRQ 9, 10 or 11.. 9 being the
best 10 second best 11 third best.. On many servers IRQ 9 is allocated to the USB controller so its unavailable at times. Note check to make sure your hard disk is not using the same IRQ as the sound device!


until I poked around with the above info "Skype would not function well" mic not recording, jumps in the sound, cut-outs or plain not working at times... I'm now running the latest Skype for Linux with no problems




housty.

Of course you say that because you've tested it on many other distros.

Good idea. I'll run a single-core kernel on my dual-core machine, so the system scheduler uses only 50% of available processing resources - and I do that in order to reduce Skype latency by a few microseconds.

Skype performance doesn't depend on your hard drive at all (OK, you have to load Skype in order to run it, so you may save a second at boot) The only time it actually uses the drive is when up/downloading files, and believe me: Even with DMA switched off, the drive will not be the bottleneck.

A soundcard without a DAC is not a soundcard, because it won't play sound. At all. Unless it has a digital output and your stereo has a digital input (in which case the number of DACs is completely irrelevant, as no analog signals are involved).

And the reason for this is?
"9 is the best, 10 is second best". I'm sure you've got benchmarks that tell me why.
Sorry, this is bullshit. And just because you've got a weird motherboard and/or BIOS where PnP doesn't work correctly (you've got PnP support in the kernel, don't you?), doesn't mean that everybody should try BIOS rainmaking.
I'd very much like to say "Gentoo is for ricers" (google for the popular website) if I wasn't on Gentoo myself.

It's great to share knowledge, but before sharing you need to make sure it's a bit more that just assumptions and half-knowledge.

So what then is the solution for using Skype on Linux????

Well, mine is to use Slackware 11 but I seem to have got around most of the other showstopper issues I had as described in this thread.

HTH