Thanks for your responses.
In that case, I don't understand why I'm having problems with streaming from youtube, iplayer etc. Playback is always jerky. It's been an issue since I purchased this machine. It's a HP G6 Pavilion Laptop. Here's the specs.
Microprocessor - 2.5 GHz Intel Core i5-3210M
Chipset - Intel HM76 Express
Microprocessor Cache - 3 MB L3 cache
Memory - 6 GB DDR3
Memory Max - Upgradeable to 8 GB DDR3 (2 DIMM)
Video Graphics - Intel HD Graphics 4000 (up to 1.65 GB)
Hard Drive - 1 TB SATA (5400 rpm) Up to 24 GB partition for system recovery
Multimedia Drive - SuperMulti DVD±R/RW with double layer support
Display - 39.6 cm (15.6") HD BrightView LED-backlit (1366 x 768)
Network Card - Integrated 10/100 BASE-T Ethernet LAN
OS ... Windows 8 64
I've enabled hardware acceleration. I've also disabled it. Flash is always kept up to date. My display adapter driver is up to date.The problem is even worse when using Firefox ... so I don't use it for streaming. Could it be a problem with my ISP. My broadband speed is usually a pretty steady 20mb. Ping and jitter are negligible. Is there anything else I could try? Change anything in 'Advanced' Internet Options in IE?