That does seem a little odd, if i am not mistaken windows reserves the amount of vram your video Card has as a mirror to use as a backup for that memory, it also reserves the required memory for anything else you have added I.E. sound cards t.v.tuners etc... plus a few hundred megs for. Windows itself.
please include more information about your system so that we can get a better idea if thats it. Otherwise, idunno what to tell you, im currently rocking a fx 8120, 16gb and a dinky radeon hd7770 1gb on a 1366 x 768 hd tv and the number of games i play that really tax my system are few, slowly getting bigger over time, but i only have 1gb on my card and that is my next upgrade and biggest downfall. If games are unplayable like you say and you dont have a giant video card to eat up that system reserved ram, thats probably a sign of not good.
One last thing to mention, honestly i am not completely ''familiar' with win 8/.1, i have installed it and used it at work, but IM still on 7 and if 8 does recognize ram differently i have not had the need or opportunities to really play with it, use it regularly to know that, but one would think with the nose poking i do on the internet i would have seen that, but the net IS a big place.......
UPDATE: if your game performance is low with an amd FX, it is almost a requirement to go into your bios and turn off any and all power saving features, as the frequency switching the chip does to save power can cause hang-ups, a downfall of the FX line. there area plethora of great FX overclocking guides out there to help you know what settings to change, even if you dont overclock it greatly helps. my 8120 is horrible at stock settings so i give it a mild boost from 3.1GHz to 3.5 just for the added stability. all i did was change the multiplier and turn off the power saving features and boom, no stuttering. that is all it took and without liquid cooling on this space heater that's as far as i want to take it or tinker with it, but as some might see the need for tinkering a bad thing, 'why doesn't it just work?', i wish i had the cooling to do more. unfortunately you sorta bought the mid 80's Harley Davidson of CPU's; great machine that will last a long time and still be competitive, but you have to keep your toolkit with you at all times 'just in case'. if plug and make it work is your thing then you should have gone intel. but this doesn't solve your memory issue and everything concerning your performance should really be in a different thread to keep things tidy, i just remembered this in an 'AHA' moment and had to share before the thought went away because its been a while since i tinkered with mine.
Facebook
Twitter
Instagram