Can't watch youtube videos higher than 144p

  welshflag 16:50 07 Apr 2018

iMac (24-inch, Early 2009) OS Yosemite 10.10.5 Processor 2.93 GHz Intel Core 2 Duo Memory 8 GB 1067 MHz DDR3 Graphics NVIDIA GeForce GT 120 256 MB 300 Gb free on HD Firefox (latest)

For some reason anything above 144p just keeps freezing the video every few seconds, although the audio streams OK. Really frustrating and it happens without anything else running in the background. It happens whether flash is running or not I'm loathe to update my imac because of cost issues, but would welcome suggestions for the most cost-effective way of doing whatever needs doing so I can watch videos in at least 750p! Then again it may be something happening in the background that doesn't involve money - I hope you guys in the know will have an answer.

Thanks in anticipation...

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

EE 5G review: How fast is 5G in the UK?

Grad Shows 2019: The Best New Illustration and Graphic Design Talent from Central Saint Martins

MacBook Pro 15in (2019) review

iMac Pro 2019 : date de sortie, prix et fiche technique