An "I won't quit you SageTV" Thread

[PhillJones]

Originally Posted by stevech

you mean windows file sharing has so much overhead that it cannot fill up the bandwidth capacity of 1000BT, I think.

I don't believe so. Adventures with big files and a stopwatch confirm that it you get the same transfer rate using 100BT as 1000BT. Not just similar, it was the same. I was using a small lan with minimal network traffic, I had a PC with both cards in and just swapped the cable back and forth. I verified that 1000BT rate was possible by performing the same experiment using filezilla.

[stevech]

What I've found is that the gigE speed I get is very much dependent on the PC's speed, when using Qcheck for I/O speed. Not Windows file system. Best I've seen is 500Mbps with Qcheck between an AMD4200 and a Pentium-M 2GHz laptop I have which has gigE. WIth an AMD1300 and gigE, it's more like 200Mbps.

But that's all using Qcheck.
Haven't tried FTP/fileZilla.

I got into this from buying a D-Link gigE switch for $28. Its user manual/spec has a typo on max packets per second - D-Link thanked me for pointing that out.

[Taddeusz]

It also depends a lot on how the gigE adapter is interfaced to the computer. If it's through PCI you will never get full speed since it has to share the bus with everything else. Proprietary interface or PCIe are the only way to go with gigE. Although I did get fairly good performance out of my Intel PCI adapters.

My SageTV server is still on a PCI card. The other two computers I have are NF4 chipsets which have the gigE built into it.

[stevech]

Thanks. I should have looked at when PCI runs out of gas for gigE.

[Taddeusz]

PCI has always been out of gas for gigE. PCI simply cannot provide full bandwidth to a gigE adapter while also sharing it with every other PCI device in your system such as audio, hard drive controllers etc. Even though PCI is still around it's a sinking ship. It just doesn't provide enough for modern tasks.

[stevech]

And what of PCIe?

[Taddeusz]

The standard 32-bit 33Mhz PCI bus only has up to 133MB/s of bandwidth for the entire bus. Meaning that bandwidth is shared by every device on the bus.

By contrast PCIe is completely different. Revision 1.1 of PCIe can carry up to 250MB/s per lane and is an unshared point to point bus.

The raw bandwidth required for gigabit ethernet can fit within that of regular PCI but leaves very little left over for the rest of the devices in the system. PCIe on the other hand provides more than enough on a 1x slot and is not shared by any other device in the system.

I will not lament the final passing of PCI even though I still have a fair number of cards still running on it. I just hope it doesn't drag out like the death throws of the floppy drive.