System Overhaul: TL;DR warning

Thank you for reading my first post here!

My current desktop system is sitting collecting dust, being superseded by my gaming laptop, that i got for a steal this summer. That can't be allowed to continue, desktop gaming should be king, also i am afraid that dual-core systems like mine just wont cut it for gaming in the years to come, as more and more games try to grab as many cores as possible.

 My desktop computer looks like this:

Core i5-660 3.3Ghz - Clarksdale
Gigabyte GA-P55-US3L rev 1.0  
2x2gb+2x4gb KVR1333D3N9K2 Kingston Value Ram DDR3
Corsair CX750M PSU
Gigabyte 560ti/OC

All of it sits in an old HUGE Antec case that weights a metric ton, it is more roomy than a cathedral so there's plenty of space for my lazy-mans approach to wire management :)

Been looking jealously at the 8350(the 4ghz version), it seems to be loads of bang for very little buck, but i am somewhat confused when it comes to motherboards (haven't had an AMD cpu since socket A), but the ASUS SABERTOOTH 990FX, rev 2.0 looks nice but compared to many other boards it carry a hefty price, a more budget friendly alternative would be a nice suggestion, also i wont be overclocking much if at all.

Speaking about budget, do i need newer faster ram or will i be able to game comfortably with the ones i already have.

for the graphics card i have more or less set my heart to the R9 280x as it seems to provide alot of bang for not a whole lot of buck, please let me know if you think i should take a look at another card that is better in terms of price/performance.

I hope i did not butcher the English language too much writing this post as it is not my first language :-)
Also thank you for your generous replies!

You weren't really clear about what you wanted. How much are you looking to spend exactly (and what country are you in)? Do you want a fully rebuild system and just try to use as much from the old build as possible? What about the case? You complained about it being heavy. Do you want to look at going with a small form factor build? Also, a lot of people think that the AM3+ socket is dead (looking at the most recent roadmaps from AMD shows no enthusiast cpus coming anytime soon), so it might be a good idea to go with Intel at this point. Modern games do use more and more cores, but they are also almost always gpu limited, so I doubt that you would see much of a difference there, but older games that don't utilize more cores do better with intel cpus (since they have better single threaded performance) so AMD isn't the obvious choice for a cpu at the moment.

Hah, i knew i would ramble on and forget important parts :)

I hail from Denmark, i am looking for a decent gaming experience using as many parts from my previous build as possible, the PSU is brand new so that is a definite keeper, i would like to reuse the ram aswell if it wont slow down the system overly much, and I am happy about my case its a good case, roomy but heavy, i have my gaming laptop for the gaming experience on the go and i travel quite much . 

1080p, no need for ultra settings, a nice mix of high and mediums will do it for me, and i plan to upgrade the system again in 3-4 years, that usually means gpu, cpu and motherboard + what else that is required.

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my budget is around 550 euro, for cpu , motherboard and gpu
I have my eyes on the amd 8350 4Ghz ( that i hope will last me years) @ 175 euro
The ASUS SABERTOOTH 990FX which is like 160 euro, a cheaper alternative to this would be nice, i am not hellbendt on one brand , it can be a gigabyte, MSI or whatever, 99% likely not to overclock 
the R9 280x , cheapest one i can get currently is a sapphire  and that is like 260 euro, if i can get a better card at the same price range please let me know

or jump ship and get a i5 4670K (they are cheaper than the 4670 at the moment around 195 euro) and perhaps the  Gigabyte G1 sniper B5 at around 95 euro. ( http://www.gigabyte.eu/products/product-page.aspx?pid=4594#sp ) and the 260 quid gpu from above?

Thanks :) 

The 8350 + Sabertooth is a great option as is a 4670k + G45 (or whatever motherboard has the features that you need). Generally speaking, the 4670k will get you better performance in game, but it is likely that the gpu would be the bottle neck with either of these cpus in most games, so really either would work. In the chart below, the 3570k is a little lower than what would be expected from the 4670k (since it is the upgraded version of the part) so really, it isn't much of a difference there. Games like BF4 however are very much gpu bound, so most any cpu will do the job and do it well. But as you can see in the article linked below (couldn't grab just the picture) older games that aren't threaded well just don't do as well with AMD chips.

http://www.bit-tech.net/hardware/2013/06/12/intel-core-i5-4670k-haswell-cpu-review/5

 

As far as the ram goes, it should be fine. If I'm not mistaken, what you have now are 1333. That should be fine for gaming.

https://www.youtube.com/watch?v=W0L_KFKJYvg

 

The psu will be fine for any single gpu configuration aswell as many multi-gpu configuration, so you are set there as well. Just do be sure that your case has decent airflow. Heat build up is a major cause in lowering the lifespan of computer parts. As long as you have a few fans running, you ought to be ok, I just want to make sure that things go smoothly for you (also because your ram doesn't have a heatsink if I'm not mistaken, which shouldn't be a problem as long as you have some airflow).

 

P.s. An after market cpu cooler such as the hyper 212 would give some nice airflow directly over the ram, which is something to consider. Again, not a huge deal, but I would bother. You get some better cooling for the cpu, better airflow through the case, and some airflow over the ram.

Thanks for the input 1920.1080.1280.720p it helped alot, and i decided upon the 8350 as it was the more budget friendly of the two and that i believe i can get many years of good gaming out of it.