New PC: biggest bang for the buck?

[Earl_UK]

do you run your os and apps of a SSD, this makes a huge improvement, then ram finally cpu

[tom886]

Thanks, OS and Apps are installed on SSD.
Ok, first upgrade will be the RAM

Thanks again

CS
Tom

[avarakin]

Probably it is too late for response about upgrade, but here it goes:
I run PI on 8gb of RAM and never saw a need for more memory because I never noticed swapping. 
I also doubt that Ssd would increase performance much.
PI is all about number crunching and for that you need CPU and not Ram or Ssd. Keep in mind that some CPUs have many slow cores (AMD) and some have fewer but faster cores (Intel) . For PI I would chose fewer but faster cores, i.e. Intel.
IMO i7 4770 and similar are the best choice right now. A CPU and motherboard would run for around $300 which is not much.

Alex

[georg.viehoever]

...
I also doubt that Ssd would increase performance much.
PI is all about number crunching and for that you need CPU and not Ram or Ssd....

Alex,

you are right that number crunching is an important aspect of image processing. However, I/O performance is also important, especially for operations such as image calibration and stacking that need to read/write lots of data from/to disk. Also, PI appears to write to disk quite frequently, for instance to enable undo operations. Have a look at the PixInsight benchmark http://pixinsight.com/benchmark/ that clearly indicates that SSDs are beneficial - at least for this benchmark.

Georg