NO! dellon is a liar, complete load of crap
i've inspected his so called mods myself, he has gone as low as the following to the dx9 dll:
12.4, the last driver that included both GCN+legacy was let's say 5.5mb (as an example, i dont remember the exact sizes)
12.5, the first driver that removed legacy was 4.8mb
what he did was put a totally random 11.7 (example version) dll that happened to be the last driver that was around 4.8mb in size, it supports all gpus but it has much reduced game profiles & bug fixes, all drivers get larger & larger as time goes on until a new set of legacy is removed & the cycle repeats, so he pretended he released 12.5 for legacy & the casually suspicious users will see similar filesizes thinking it's 12.5 modded
how do i know it was (the example) 11.7? maybe cuz
i'm the one poking at the drivers since 2009 to find profiles, i confirmed that the profiles in his driver were the same as the older one (i even collect dlls of most releases so i can easily compare at any time)
all that said... there is a different reliable honest user on guru3d named
kevsamiga1974, but he was focusing on dx10 legacy when i hung around there, he was packaging up a frankenstein driver with the goal of being as few bugs as possible (dxva, youtube, crashes, etc), even if it meant fewer game profiles, while i prefer the most game profiles & then placing dlls from different driver versions into individual programs that have a problem
anyway, the goal here is smooth youtube.... well i have an xp next to my foot with a 9800pro (the x800xtpe died unfortunately) & an athlonXP-m overclocked, nforce2, so it's worse than yours, maybe i should check how bad youtube is, but from what i remember, 480p was the largest usable size
the first things you can try: FF vs IE (well probably not if it's max 8 on xp) vs chromium based (opera, chrome), plus check flash vs html5 in FF & chromium, maybe even check flash with hardware acceleration disabled, who knows which will end up fastest
there is also another crazy workaround... download the videos with
youtube-dl.exe, you might get partially working gpu accelerated decoding in MPC or VLC rather than the browsers, or at the very least less cpu usage compared to the browsers (especially when using efficient decoders like coreavc)
finally... maybe you should replace the box & i dont mean spend hundreds of dollars either, i wonder how a raspberry pi will handle itself given that people run xbmc/kodi on it to play HD videos
