Can a conviction for a speeding offence have an adverse impact on GC application?
The sentence carries a fine and a 4 points penalty.
The answer may heavily depend on the circumstances but in general a speeding ticket won't be an issue according to instructions to I-485:
NOTE: Unless a traffic insident was alcohol or drug-related, you do not need to submit documentation for traffic fines and incidents that did not involve an actual arrest if the only penalty was a fine of less then $500 and/or points on your driver's license.
Additionally on the form itself
Have you ever been arrested, fined, cited, ...., excluding traffic violations?