FX-8120 and GTX 660 SC, wanting to upgrade, SLI, or R9 280x / GTX 770? or CPU Bottleneck?

[Zombified7x60]

Specs:
Motherboard: Asus Sabertooth FX990 R2.0
CPU: FX-8120 8-core (stock 3.1ghz, running at constant 4.0GHz)
RAM: G.Skill Ares 16gb @ 1866MHz
GPU: EVGA GTX 660 Superclocked 2gb
PSU: Corsair CX750

Now my biggest concern is CPU bottlenecking, and whether SLI would be worth it for games such as Crysis, Battlefield 4, Tera Rising, and Rift. It would be cheaper as I'm already running a GTX 660 but a single card is always better for heat and power consumption. Yes I know Intel is faster 95% of the time and I will upgrade in the future but I'm guessing this FX-8120 is fast enough for the next couple years for gaming.. am I right?

My PSU is making a constant whining noise and it seems to get louder as loads are increased, could this be a faulty PSU that needs to be replaced? Should I worry about this noise?

Thanks again for the help everyone. I can't explain how helpful Tom's Hardware has been!

 

[pfunkmd]

That 8120 can feed two 660s
I think people worry to much about bottle necking I had a i3 2320 feeding 2 hd 6870s and 2 r9 270s it was fine. I later switched to an i5 3570k and didn't much difference if any.
I

 

[photonboy]

http://lanoc.org/review/video-cards/5953-nvidia-gtx-660-sli-performance?showall=&start=2

Get another GTX660. Either get the same EVGA, or the Asus depending on price. I think the Asus is $200 at pcparticker and your EVGA is around $220 to $240.

Normally I recommend a single card, but I think this is the best value for you.

POWER SUPPLY:
It's hard for me to say from here if it's a problem or not. If you've noticed a big change then it could be a sign that it's failing and adding another GTX660 might kill it. Again, I just can't say.

I believe your Power Supply has enough PCIe connectors, but you should double-check that.

BOTTLENECKING:
Yes, you will have games that would run better with an i5-4670K even with only one card. Skyrim for example is about 40% slower with the FX-8320 but it's more of a worst-case scenario. However, the best VALUE for you is still to add another GTX660 for now then build a new system in 2+ years.

We should also see the FX-8320 do BETTER in the future once games can use multiple CPU cores better. The FX-8350 and i5-4670K I think are roughly comparable in Battlefield 4.

 

[Zombified7x60]

I have the 8120 which is the Bulldozer version and is much slower than i5-4670k and 8320 in.. well everything that I've read so far. I sold my GTX 660 and will sell the rest of the system soon unless I can't find any buyers. I plan on i5-4670k and a GTX 770 unless my thoughts below are wrong..

Can you guys give me an opinion on going 3770k vs 4670k? Is there any reasoning to even consider going 3rd gen i7 instead of 4th gen i5?

And what about the "Dual" cards? There's a GTX 770 Superclocked and a GTX 770 DUAL Overclocked, I'm trying to figure out the difference since I'm pretty set on the EVGA GTX 770. There's an EVGA version with the ATX cooler and a version with the Titan cooler ($40-50 more), would the Titan cooler be worth the price difference? Should I stick with 2gb VRAM or consider a 4gb card by a cheaper brand? (Zotac, PNY). Everyone's talking about 4k like it's coming out tomorrow but realistically speaking.. what would you do?

As for the PSU: the sound worsens as loads are increased, even things as simple as me moving my mouse from one picture to another on a webpage will cause different frequency type sounds. I'm really stumped. I know it's my PSU squealing because if you stick your ear right next to the filter, it's 4x louder. I haven't noticed any differences performance wise and everything still seems to work perfect.