CFULLHDMA and GIGABIT

Although I like the articles on MPCCLUB I do not always agree what is written.

Today I read a story about: Media Players: ‘2 cents from a stranger’.

Quote:

Another example is the network connection on many of the media players today. People would expect them to have high throughput GBIT or minimum 10/100 network connections for transferring files to a media player which has an internal hard drive. What‟s not transparent is that media chips used (mostly Sigma Designs) have limited I/O performance that deliver nowhere near what you’d expect from GBIT or 10/100 network as you experience daily on a PC. Limitation by the chipset‟s performance is about 4-5 Mbit for 10/100. Did the manufacturer lie to you in any of both cases? No. The network connection is GBIT or is 10/100, it‟s just a name; only, it does not perform as you’d expect, due to limitations of the processor but it does not change the fact the player has a GBIT or 10/100 network connection.

In this story it is stated that the I/O performance of SD 8635 is limited and it’s performance is about 4-5Mbit (10/100) and that Gigabit is no use. Without any further explanation other than ‘limitation of chipset’, This is ‘true’. But if such statement is told over and over again, you can think that Gigabit is impossible and only a marketing trick and totally cannot get better performance than 10/100.

So I think I have to correct some things… Prepare for some technical details:

Standard MediaPlayers do use the MII connection of the Sigma Designs chipset which is indeed capable of 10/100 Network PHY with throughput speeds up to 4~6, maybe 7 Mb/s. 

Normally it is common to use RMGII or PCIe and not PCI to connect to a Giga PHY since the throughput of PCI is ‘too’ slow for a real Gigabit connections. Gigabit need a lot of processor power from the CPU side. As the clock of SD8635 is only 300MHz you can imagine that 100% Gigabit speed is impossible (60 to 110Mb/s).

When I check the Conceptronic CFULLHDMA, which has Gigabit, you can wonder why they choose for Gigabit rather than 10/100 not only being it a ‘marketing trick’ when you read this article.

The reason is very simple: they did not use the MII interface but connected the Gigabit PHY to the PCI interface. This will result in a higher speed for the Gigabit PHY but not the full speed as explained before. (you should use RGMII or PCIe).

During long time testing I got a steady 11Mb/s throughput speed. 

We can discuss about the fact that certain movies will not extend the speed of 10/100 but I’ve seen that a Gigalan can and will achieve better performance using Gigabit rather than 10/100 especially when playing ’critical’ high bitrate HD content.

Yes, 11Mb/s is not a full gigabit speed but is giving just that extra boost. So writing that Gigabit is ‘impossible’ or a fake marketing trick is not correct. (as long as you implement it as described above).

Note: the part about UPnP servers not capable of supporting subtitle files is also not totally true..  The Conceptronic CH3SNAS in combination with C54WMP or CFULLHDMA can do that .. It has all to do with ‘active-request’ for the SRT file rather than being passive waiting for it, what is common for UPnP AV based Players.

note: this message is my personal opinion .. nothing else..

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