I have Comcast 768K/6M package, but my upload speed can only reach 400 Kbps.
The Comcast technicians came several times, they changed the cable line, adjust the signal strength,
the upload speed indeed increased........ from 200 Kbps -> 400 Kbps............. still far away from 768 Kbps.

The technician also tried to use their own laptop, same speed. They also confirmed the cap settings are correctly set to 768K/6M.

There are no viruses, no spywares.

After their adjustment, the ping value decreased from 400 ms -> 50 ms.............. it's good, but the speed still under 400 Kbps.

They've tried to solve the problem for several weeks,, still can not figure out how to solve this.
Anyone can help??? Thanks.

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CPU Centrino 1.5GHz
OS: Windows XP Professional Edition SP2
RAM 512 MB
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::::::::::.. Upload Stats ..::::::::::
Connection is:: 375 Kbps about 0.4 Mbps (tested with 579 kB)
Upload Speed is:: 46 kB/s
Tested From:: http://testmy.net/ (main)
Test Time:: Mon Apr 18 2005 17:57:11 GMT-0500 (Central Daylight Time)

Connection is:: 2995 Kbps about 3 Mbps (tested with 2992 kB)
Download Speed is:: 366 kB/s
Tested From:: http://www.testmy.net/
Test Time:: Mon Apr 18 2005 18:06:30 GMT-0500 (Central Daylight Time)
=========================================================================================
My cable modem is Motorola 5100, the following data is the signal condition
Downstream    Value
Frequency    627000000 Hz Locked
Signal to Noise Ratio    37 dB
Power Level    14 dB

Upstream    Value
Channel ID    3
Frequency    19500000 Hz Ranged
Power Level    54 dBmV
=========================================================================================
The following info is tested from http://ttester.broadbandreports.com/tweak

Your Tweakable Settings:
Receive Window (RWIN):    824320
Window Scaling:    4
Path MTU Discovery:    ON
RFC1323 Window Scaling:    ON
RFC1323 Time Stamping:    OFF
Selective Acks:    ON
MSS requested:    1460
TTL:
(less any hops behind firewall)
   67
TTL remaining:    47
   2. Test 146000 byte download
   Actual data bytes sent: 147460
Actual data packets: 101
Max packet sent (MTU): 1500
Max packet recd (MTU): 1500
Retransmitted data packets: 1
sacks you sent: 20
pushed data pkts: 1
data transmit time: 1.243 secs
our max idletime: 119.0 ms
transfer rate: 88922 bytes/sec
transfer rate: 711 kbits/sec
This is not a speed test!
transfer efficiency: 99%
   3. ICMP (ping) check
   Minimum ping: 49 ms
Maximum ping: 140 ms
Ping stability:
119 50 80 54 76 140 49 51 80 51
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The tweak program I'm using is cablenut with the Vanburens's Cable & DSL 6000 768.ccs settings
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The ethernet cable is directly connected to the cable modem.

what internet browser you using? using other browsers like: firefox, opera. can help increase speeds. i would prefer using firefox   

http://testmy.net/topic-3652

I have noticed that upload tests are much slower with Mozilla Firefox, but when I test with Internet Explorer this is what I get:

::::::::::.. Upload Stats ..::::::::::
Connection is:: 694 Kbps about 0.7 Mbps (tested with 579 kB)
Upload Speed is:: 85 kB/s
Tested From:: http://testmy.net/ (main)
Test Time:: Tue Apr 19 15:40:15 PDT 2005
Bottom Line:: 12X faster than 56K 1MB upload in 12.05 sec
Diagnosis: Awesome! 20% + : 108.41 % faster than the average for host (Comcast.net)
Validation Link:: http://testmy.net/stats/id-KFSGCDIUO


and it is true the download speed test are much faster with Firefox. Just thought I might add.

Ignore the post before this I messed up the modem model name, Correction:

And one more thing I saw that you are using a Motorola SB5100. Call Comcast and ask them to get you the SB5120, thats then new out right now, that should help. Your modem might be old, give it a try.

nice upload 

Actually, I just called Comcast right now, and the tech told me the newest modem is the SB5120, I'm not trying to argue or anything but if u dont beleive me call them and ask.  One more thing, he said it depends on your area, probably they only give the SB5100 in your area. 

have u asked Comcast yourself?  how would it be older if the number goes up? its called a SB5120, seriously give them a call.  and I live in a city, lol. 

Its working just fine for me, Comcast told me that they do have the SB5100's but they recomend the newer one.