Here's my experience with the TM Streamyx lately.
Modem AZTECH DSL600EW.
Suspects: Modem, wiring, connection to TM...

From the Aztech modem:
Connection Status Connected
US Rate(Kbps) 448
DS Rate(Kbps) 2048
US Margin 7
DS Margin 31
Modulation MMODE
LOS Errors 0
DS Line Att 16
US Line Att 5
Path Mode Fast Path

Near end F4 loop back count 0
Near end F5 loop back count 0

Occasionally the line would be good for browsing, gaming, etc.. which will only last from anywhere from 30mins to 180mins. Then it'll return to its sluggish crawl.

Swapped a a friend's ZTE modem in to verify:

Local Line Att 15.0 dB
Remote Line Att 4.0 dB
Local SNR margin 27.5 dB
Remote SNR margin 8.0 dB
Self test Passed
DSL Standard G.Lite
Trellis Coding Disable
Framing Structure Framing-3

AS0(kbps) Down (Fast - 2048)
LS0(kbps) Up (Fast - 512)

Pings to Gateway still has time-outs. Tested with 100 packets, ranges from 15% - 30% losses.
Area: Near Kelana Jaya Exchange
Reported matter to 9515, and after a week of bumming around, i finally have a reply saying they have problem with their DSLAM...

Annoying MAX!!!