What is the length of your cable? Cheap substandard cables works fine if it's short, but not that well if it's too long. And avoid those shitty flat cable. You can get ready made patch cable of good brand of cable, but most shops now sell only cheap craps. But some shop do sell custom length of good cable. You can find custom length cat5e cable in garage sales as well.

It affect my ex-company office in Kelana but not at my home at sri petaling. Pinging to the remote gateway ip results in 20+ms ping with significant packet loss as well. The packet loss is the main issue which cause severe performance degradation.