5 years on from buying my current system, its time for an upgrade this year. I have a budget of around £1000, and i can build the following system for round about £900:

Intel® Core™i7 Quad Core Processor i7-3770K (3.5GHz) 8MB Cache

ASUS® P8Z77-M: MICRO-ATX, USB 3.0, SATA 6GBs, ATI®CrossFireX

16GB SAMSUNG DUAL-DDR3 1600MHz (2 X 8GB)

2GB NVIDIA GEFORCE GTX 650 - DVI, mHDMI, VGA - 3D Vision Ready

After tweaks to the CFG etc, would i be able to run FSX at a more stable setting (currently average 15-20FPS on a good day at UK2000 Manchester with the PMDG MD11)?

Cheers

Get faster RAM and a faster GPU if you can squeeze them into your budget or you may regret your purchase eventually.  Also make sure to have good cooling so you can overclock that CPU and get the most out of your system.  

I would agree. Go for something like a 2GB 660Ti and some 2133 Mhz RAM.

For 1300 i can get the following:
 

Intel® Core™i7 Quad Core Processor i7-3820 (3.6GHz) 10MB Cache

16GB KINGSTON HYPERX BEAST DUAL-DDR3 2400MHz X.M.P (2 x 8GB KIT)

ASUS® SABERTOOTH X79: SOCKET 2011, R.O.G

2GB NVIDIA GEFORCE GTX 660 Ti - 2 DVI, HDMI, DP - 3D Vision Ready

Could just be inside my price range come years end

I wouldn't change the CPU, the 3770k is the fastest quad core chip currently available.  The other system you've spec'd will provide a good deal more video horsepower but is actually a downgrade in terms of CPU performance.  FSX needs a fast CPU above all else.  See if you can change the RAM and the GPU on the 1st system to that of the 2nd.  

Yep, can do that, and its still with in price range, so when it comes to upgrading later in the year, i'll build a system around the 3770K with the 2nd units ram. 

Cheers guys 
 

If you're not building now, there's not much sense in putting together a parts list since new parts come out constantly...  Check again when you're ready to build.  

If your budget is hurting with the video card upgrade, get the i5 3570k. It will offer very similar preformance for 100 l