From what i have been reading around the web,it seems most issues with BF4 are with W8-8.1 and with BF4 in general.
One of my clanmates actually uninstalled W8 and installed W7 just to play BF3 and BF4.
Running tri fire with BF4 is a little overkill anyways.I run 2-7950's in crossfire on ultra 1920X1200 with no issues whatsoever,In fact my 6950 crossfire also ran it fine in Ultra.
What resolution are you running?
AMD Phenom II 1100t @4.0Ghz <Asus sabertooth 990fx<2x Gigabyte 3G 7950's in crossfire<Samsung 500G 840 EVO SSD<16G G-Skill Ripjaw 1600<2-samsung 24" monitors 1920X1200<Corsair AX1200W psu<W7 pro 64<Logitech G19 keyboard<Roccat kone pure mouse<Cooler master HAF932<Corsair H100i water cooler<Zalman ram cooler<Sound Blaster X-Fi Titanium Fatal1ty Champion Series<Logitech Z5500 speakers<Roccat Kave 5.1 headset.