Stuttery playback Premiere Pro CS6, I know this is a FAQ but I can't find a fix.

Question

I'm going to list as much as I can if I forget anything please don't be harsh, I will make sure to add/reply with what I missed. Please bare in mind I may add stuff that is not a cause of the issue but I'm just trying to give you as much background as possible.
     Basically I have been using Premiere Pro for quite a while (around 4-6 months with no issue) I came over from Sony Vegas and have never looked back, (I use Ps, Au, Ai & Ae also so the intergration is perfect) a couple of weeks ago I started havng issues with playback I will add my specs below and you can see I have quite a beefy PC which makes me think it's maybe a hard drive issue. Everytime I open Pr I hit the 'HDV 1080p 30fps' preset drag my clip in and hit 'change sequence settings' Screenshots: http://imgur.com/a/kXG8n
Then as I mentioned about 2 weeks ago I started having stuttery playback (frames will stutter foward and after around 10 frames with jult back around 4-5 frames), I found a fix of copying & pasting my timeline into a new sequence but this fix is no longer working. One thing I have noticed is that the work area render bar used to be red and is now yellow when I add my footage, I am using the software MPE (I have an AMD GPU and as far as I'm aware I cannot do any different) I have 10gb of ram allocated to Adobe products in the 'memory' tab. I have tried 'optimizing rendering for' both performance & memory and giving it all 15gb of RAM that I can but it all makes no difference. Screenshots: http://imgur.com/a/Guanm
I have been googling it every day for the past two weeks, I even have the search 'stuttery playback in premiere pro' bookmarked and have have tried every possible thing. I have been forced to go back to Vegas for the moment and I want to be using Premiere Pro again so can anyone help?
i'm aware that it could be a hard drive issue as I only have one HDD, this has never been an issue before and I don't wanna go out and spend unnecessary money. I appciate any response, I'm not sure how these forums work with upvotiing or anything like that but if you could share this discussion with people that would be fantastic, thank you very much for your time.]
My PC specs: (I have put all that I think is relevent, if anything else is needed please let me know).
Processor: Intel® Core™i7-2700k Quad Core (3.50GHz, 8MB Cache) + HD Graphics
Motherboard: ASUS® P8Z77-M: MICRO-ATX, USB 3.0, SATA 6GBs, ATI®CrossFireX
Memory: 16GB SAMSUNG DUAL-DDR3 1333MHz (2 X 8GB)
Graphics Card: 2GB AMD RADEON™ HD7850 - DVI,HDMI,2 mDP - DX® 11, Eyefinity 4 Capable
Memory: 1TB 3.5" SATA-III 6GB/s HDD 7200RPM 32MB CACHE (Please note: this drive is currently writing at 183 MB/sec)
Once again thank you for your time.

Answer 1

Part of the reason for such stuttery playback performance lies with the limitations of the single SATA connection (channel) itself. You see, SATA is not full duplex, but only half-duplex. That means that a block of transfers going in one direction must be completed before a block of transfers can even begin in the opposite direction. Think of the SATA channel (single connection) as a single-lane stretch of highway with traffic signals at each end. What's worse, that single disk must also deal with the Windows pagefile, the media cache, previews and various other things all going on at the same time. As a result, the effective performance of that single disk can plummet by a factor of six: That single disk, after accounting for all of the tasks it must perform at the same time as video playback, is left with only about 32 MB/s of bandwidth available for Premiere Pro.
In other words, that single disk is being severely overworked as it is.