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#1 2009-01-29 00:11:34

phosphato
Member
Registered: 2009-01-10
Posts: 5

Jumbo Frame testing speed for DGE-560T PCIe adapter and DNS-323

Hi all:

I just bought a D-Link DGE-560T PCIe Ethernet Adapter and these are my speed tests. Tests have been made with a 8GB filesize.

My small NET looks like this; PC (with new PCIe adapter), Switch DGS-1005D and NAS DNS-323. CAT5E cable. Switch supports Jumbo Frames.

PC had built-in Gigabit Adapter "Attansic" brand, but I was very disappointed with transfer speeds between PC and NAS, 17MB/s for Read and Write, unstable speed rate and not fast enough for FullHD 1080p viewing with a lot of judder playing high bitrate movies. Even with Jumbo Framing enabled 4K or 9K.



After installing the new adapter on PC these are my results. Transfer speeds are much more constant now than built-in gigabit adapter.

Normal Operation
19MB/s Read

Jumbo 4K
25MB/s Read

Jumbo 9K
29MB/s Read


19MB/s Writing with any configuration.

Now I have no judder when viewing 1080p with high frame rate movies.

I hope these results can help someone.

Bye.

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#2 2009-01-29 21:39:20

oken
Member
Registered: 2007-08-13
Posts: 23
Website

Re: Jumbo Frame testing speed for DGE-560T PCIe adapter and DNS-323

17MB/sec should be enough for playing just about any 1080p content from a network resource. For example, the maximum bit rate for H.264 or VC-1 compressed Blu-ray video is 54Mbit/sec (6.75MB/sec).

What you are experiencing is probably the build-in network adaptor sucking up too much CPU time or other system resources on the computer decoding the HD content, making the video player software starve.

Anyway, good to hear that the new quality NIC fixed the issue.

Transferring data at high speeds through the network stack is actually a quite resource-hungry operation (do a 19MB/sec network transfer and look at your CPU utilization), and a badly optimized NIC driver or hardware can make things worse. This is why servers often use "TOE" network cards with parts of TCP/IP stack implemented in hardware to free the CPU of the load.

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#3 2009-01-29 23:19:26

7oby
Member
Registered: 2008-11-10
Posts: 12

Re: Jumbo Frame testing speed for DGE-560T PCIe adapter and DNS-323

oken wrote:

This is why servers often use "TOE"

Good point. However last time I checked I recongized that even the very cheapest NICs and especially all 1GBit NICs support TCP Offloading. His card does as well:

TCP, UDP, IP Checksum Calculation

http://www.dlink.com/products/?pid=406

I could image a bigger impact comes from the SMB/CIFS protocol itself. It's not a particular streaming protocol. Playing back content results in frequent suspending and resuming transfers. I don't know how many TCP/IP ping pongs are required to resume a transfer. The weak CPU is not in the PC, but the DNS-323 and I can't tell whether the time required to resume a transfer is less than the time window the Host PC buffers while playing back.

Maybe uPNP is a better protocol. Don't know.

EDIT: okay maybe the "PC had built-in Gigabit Adapter "Attansic" brand" really didn't support TCP/IP offloading. But as I said: Last time I checked even the very cheapest 1Gb/s ones did support that.

Last edited by 7oby (2009-01-29 23:21:20)

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