4GB or 8GB 1866mhz ram for APU build

I got an A8-5600k free from AMD Fan Day. 

My question is 

Is 4GB at 1866mhz okay to have or should I bump it up to 8GB?

Will I see a performance boost if I upgrade?

I currently have 4GB at 1866mhz in a dual channel setup on my AsRock FM2A85X Extreme4-M motherboard.

I have the A8-3800 and 8 GB running at 1600mhz. The speed is the key factor here not the size unless you run very heavy programs. If your motherboard supports higher than 1866mhz go for high ram. Because the system memory is used as video memory. And the faster the ram the better frame rate and if you overclock you will be able to push even better video performance.

Your not realy going to see any differnce running 4-8gbs on a apu unit anless your running crossfire with the apu

Yeah my motherboard supports 1866mhz natively and can oc the ram as well. 

Actually I am crossfiring with a 6670. SInce I will be mostly gaming on this should I go for 8Gb. Does my resolution matter as well? I am playing on a 32' 720p HDTV.

If your running at 720p then no its not going to improve your gameing but hey if you can get a extra stick cheap slot one in.

Ram is going up in price fast lately get a stick while its cheaper 

Ok then I will see what I can do. Thanks.

go 8 gb. I mean, seriously, my browser uses like 2-3 gb alone, plus windows and vram.

3gbs for your browser O_O what are you useing?

40 tabs of Chrome, probably. Also get 1866 RAM if you can, or even faster.

Which web browser are you using? This cannot be chrome? Firefox?

I'd really recommend 8 gigabytes, and as much of it as possible. If you're only going for 4 gigs, get 2133, or 1866 that you can overclock to 2133.

Yeah I only had $40 dollars at the time of purchasing this set of ram http://www.newegg.com/Product/Product.aspx?Item=N82E16820220560

I bought it for $30 at Frys. 

The Ram will be the first thing I will upgrade as soon as I have the money.

My browser tends to use 3-4GB by itself, as well. Firefox with 200+ plugins, usually running a 30+ tabs. I'm a mutlitasker. If you can, get 8GB; if not now, you will put it to use later, in a new build, or if you convert this build to a server - it can't hurt!

i would go 8gb, with an apu the cpu and gpu are using the same memory space so it'll be good to have plenty of it.