Jagged edges because of DSL?

[coil_nine]

Can DSL slower speed cause jagged edges on images?
Perhaps I have optimized the DSL speed so much, it is very lossy?

We are trying to switch from cable to DSL. Cable is $48 per month, monopoly in this area, and DSL is $15. I have chosen to keep the cable until we are certain we want to switch, so we have both available.

On the DSL connection, images sometimes have jagged edges. This is very noticeable on logos. For example, the page http://nyt.com has their name and the lettering has jagged diagonals. I switch back to the cable modem and I do not see these jaggies.

[trogers]

I am using a 1 mbps ADSL line from the other side of the globe and I do not get any jagged edges at the said webpage.

It could be that your comp settings are not optimized or that you have packet losses along the connection line.

What speed did you pay to get?

Post your TCP Analyzer report.

[coil_nine]

I like your sig. Missed that milestone, too.

Verizon offers 768 kbps DSL at 15 $US. No other DSL supplier in our area, and their "FIOS" is not yet available. Comcast offers 1 mbps cable at 48 $US, also no other cable supplier in our area, western Massachusetts US, somewhat rural. The measured cable speed is about 1.2 - 1.5 mbps with the TCP Analyzer. The DSL is noticeably slower, still fast enough for my satisfaction.

These analyzer results are DSL

« SpeedGuide.net TCP Analyzer Results »
Tested on: 01.06.2008 21:02
IP address: 96.233.xxx.xx

TCP options string: 020405ac010303020101080a000000000000000001010402
MSS: 1452
MTU: 1492
TCP Window: 257004 (multiple of MSS)
RWIN Scaling: 2
Unscaled RWIN : 64251
Reccomended RWINs: 63888, 127776, 255552, 511104
BDP limit (200ms): 10280kbps (1285KBytes/s)
BDP limit (500ms): 4112kbps (514KBytes/s)
MTU Discovery: ON
TTL: 53
Timestamps: ON
SACKs: ON
IP ToS: 00000000 (0)

[trogers]

Try the following with TCP Optimizer for the 768 kbps line:

General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU 1492
TTL - 64
TCP Receive Window - 17424
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Windows Scaling - uncheck
Timestamps - uncheck

Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 20
LocalPriority - 1
Host Priority - 1
DNSPriority - 1
NetbtPriority - 1
Lan Browsing speedup - optimized
QoS: NonBestEffortLimit - 0
ToS: DisableUserTOSSetting - 0
ToS: DefaultTOSValue - 80
MaxNegativeCacheTtl - 0
NetFailureCacheTime - 0
NegativeSOACache Time - 0
LAN Request Buffer Size - 32768
Then select "Apply Changes" and reboot to take effect

[coil_nine]

Problem solved, thank you!

I used the TCP optimizer and improved the speed about 25 percent.
I applied your changes and the average speed increased about 10 percent more.


However, I found the problem and solution was in the Firefox browser config file.

Images in IE were slightly smaller and smooth. I searched and discovered in Firefox you could change the default image zoom percent. I do not know how the value was changed from default 100 percent, I certainly did not. Here was the fix

http://ubuntuforums.org/showthread.php?t=479628

view the current value in URL:
about:config

search for
imagezoom.defaultGlobalZoom

Double-click on the line and change the value to 100 percent. Images are normal sized and no jagged edges.

[trogers]

I use this add-on for FireFox. Default for zoom can be set at desired value with simple right click for other values:

https://addons.mozilla.org/en-US/firefox/addon/139

[YARDofSTUF]

Unlreated, but you have 1 PC on dsl and 1 on cable?

[coil_nine]

Originally Posted by YARDofSTUF

Unlreated, but you have 1 PC on dsl and 1 on cable?

I did have 1 on cable and 1 on DSL for a few days until DSL was trustworthy. Now that both can connect to DSL, I have disconnected the cable modem.