To check this up u need to access your modem WEB Gui connect directly modem to your PC if ur gateway address is 192.168.1.1

Go to i.e or firefox browser type http://192.168.1.1  <– certain modem have different default ip address checkup your Modem Manual for instruction.

Pls note that u also can check how fast the ISP Capped your speed . If you subscribe to 1 Mbps the ISP should capped you at 1024kbps or 1524kbps. Having caps higher speed is better because u can enjoy higher speed but most ISP now capped ur speed via ur username example if u have 1 Mbps the best speed u can got is around 1.5 Mbps even though the isp capped you at 4024kbps

They are also certain issues when people subscribe 1 Mbps but the ISP capped their line at 512kbps so they can’t enjoy the true speed of their broadband. Using this tips u can check yourself whether you are capped at the correct speed.  Please note if ur ADSL is bad having high caps will have your attenuation noise higher that will cause DSL light to blink that’s why u have to read this tips.

Sample of 1 Mbps line Quality

SN Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)
Relative strength of the DSL signal to Noise ratio. 6dB is the lowest dB manufactures specify for modem to be able to synch. In some instances interleaving* can help raise the noise margin to an acceptable level. The higher the number the better for this measurement.
> 6dB or below is bad and will experience no synch or intermittent synch problems
> 7dB-10dB is fair but does not leave much room for variances in conditions
> 11dB-20dB is good with no synch problems
> 20dB-28dB is excellent
> 29dB or above is outstanding

Line Attenuation
Measure of how much the signal has degraded between the DSLAM and the modem. Maximum signal loss recommendation is usually about 60dB. The lower the dB the better for this measurement.
> 20dB and below is outstanding
> 20dB-30dB is excellent
> 30dB-40dB is very good
> 40dB-50dB is good
> 50dB-60dB is poor and may experience connectivity issues
> 60dB or above is bad and will experience connectivity issues