CPU or GPU at fault for poor video playback

[Conster]

Okay, first of all, apologies if this is in the wrong place, I wasn't too sure where to put it.
I've recently revived an old eMachines D620. I tried playing YouTube videos and it was just a horrible mess of dropped frames and stuttering. The laptop was running very hot so I replaced the thermal paste, thinking that maybe heat was the issue. However, although videos do now play much better, I can't go past 360p without dropped frames and jerkiness. Even 360p is pretty bad. My question is, is my CPU at fault or is it the GPU? I understand that both are very low end, but this is one of the laptops that allows you to change the CPU. I don't want to go upgrading the CPU only to find that it's the GPU that is the issue. CPU: AMD Athlon 64 2560e GPU: ATi Radeon X1250. Garbage yes, but I'd assume they're both able for YouTube. Driver Issue?

TLDR: Videos play like ass at or above 360p, Is it the CPU or the GPU causing the issue. AMD Athlon 64 2560e, ATi Radeon X1250. Driver issue?

 

[USAFRet]

CPU, GPU, old OS install, hard drive, temps, internet connection...all could be the issue.

 

[Conster]

CPU, GPU, old OS install, hard drive, temps, internet connection...all could be the issue.

True, however I do remember playing some older games with no issue back when this was my main laptop, which is obviously more strenuous than playing a YouTube clip.

 

[rgd1101]

depend of the encode/compression it uses, it might be more strenuous than you think.

did you look at the task manager to see what cpu utilization is?

 

[FD2Raptor]

I have an old system Core2 Duo E6320 Dualcore 1.86Ghz+GT220 (upgraded from the 2007 part 8500GT) and the 8500 GT could only be rely on to decode 720p h264 video, the GT220 can do 1080p h264 and with the extra performance increase in Windows 8, the Core 2 Duo can do 1080p h264 that isn't super high bitrate.

For your system, while I can't find info on the spec of that CPU but since the performance of a higher number part, the Athlon 64 2650e (single core), greatly lags behind a Core2 Duo E6320; and the X1250 is 2-3 years older than the 8500 GT, I'd say that the system itself is severely under-powered for HD/FullHD h264 decoding (which is the main video codec on YT).

 

[Conster]

Yeah, I guess it's just how things have moved on. I wasn't expecting 720p playback, but I was assuming it could manage 360p and 480p. CPU usage is pretty much pegged at 100%.