The problem with TSI and Youtube has been getting progressively worse over the last few months and mostly during peak time. They've likely been running out of capacity for a while but apparently just added 30Gbits/sec of capacity to Google/Youtube which was supposed to fix the problem but hasn't yet.
You're likely going to need 10-15mbit/sec to stream 1080p tho without buffering.
Welcome to the forum, I see you just joined. If you want to post in the secured direct forum with your address we can check the serviceability »TekSavvy Direct or if you prefer you can PM me TSI Jonathan . We can qualify to see if Cable Internet is available at the same time (if it's something that may interest you).
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TSI Jonathan -- Social Media Relations Team Leader Authorized TSI employee - Teksavvy Solutions Inc.