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Phoenix, AZ

1 edit
reply to xymox1

Re: Upgrade from dpc3000 to dpc3010 and slower upstream speeds

Well well well...

So I changed back to my DPC3000 and I am right back to my upstream rate of 5.5M/s using all my normal sites in speedtest.net.

I then changed to the DCP3010 again to make sure and sure enough I could only get a max of 4.3Mb/s...

I tested using 3 different servers at speedtest, I tested each twice. ALL the reults were the same.

The DPC3010 topped out at 4.3
The DPC3000 was always 5.5 which is the cap

I also got slightly better and more consistent download speeds from the DPC3000.

OK so maybe I got a bad DPC3010. I get a new one monday. If I find out that the new dpc3010 is again slower then the dpc3000 then that will be a interesting find and indicate that the DPC3000 is the better device over the DPC3010.

The transmit / rcv levels for both modems showed virtually the exact same numbers.

Anyone have any explanation ?

Im also going to get a SB6180 later in the week and will test that as well.

For reference my levels are +3 down and 42db up power. The channels dont vary much in levels.

Every single time with the DPC3000

Phoenix, AZ

Further playing. I cant be sure of course until I get my new dpc3010 on monday, but I am starting to suspect that maybe the DPC3000 might be better, at least in my cox cable area using the current Ultimate tier. This might change once they roll out 100Mb tho.

The dpc3010 is a completly different device based on a whole different Broadcom chip set. The ethernet controller ship is built in for example.

Every single chip maker is different in the 3010.

The dpc3000 uses a Texas Instruments chip vs the 3010 which uses a Broadcom.

Even the radio chips are different manufacturers.

So these are very different devices.

The upstream rate I think is cap by the modem itself, which means the chip in the unit has to do some form of rate limiting. This rate limiting might be different between Texas Instruments and Broadcom. In fact the whole way it handles the data stream might be different.

So while the upstream channels are capable of way faster then 5.5Mb/s the cap rate limiting methods might produce different results at these low speeds with different chips.

When I get my new modem, if I verify it does the same 4Mb/s vs 5.5mb/s on the dpc3000 that would be very interesting.

It will also be interesting to see how the SB6180 does on this.

Phoenix, AZ

Turns out that Texas Instruments holds a key patent on ACK filtering which has a big effect when a upstream cap is doing rate limiting. So possibly the TI based chips produce better results when rate limiting a upstream channel ?


Background »www.ti.com/lit/wp/spay014/spay014.pdf


Are you having Cox upgrade the firmware at activation?