Upgrade Q9550 system or Build new i7 950 system?

Question

Hoping someone can help with yet another upgrade or build question!
I am new to NLEs but am a fan of Adobe CS suites and plan to use CS5 Premiere and AE.  I am a hobbyist rather than a pro but I take my hobbies pretty seriously :-).  I intend to create shorts out of my video footage from DSLRs using either AVCHD or m264.  I would like my NLE system to run smoothly with multiple windows and programs (e.g., PR, PS, etc) open and I am pretty impatient when it comes to waiting for systems to process/load, etc.
It will not be used for gaming of any kind.  It must run very stably.  I never experience BSODs and I don't want to in future!
Here are the two options I am considering:
OPTION ONE:  Upgrade existing machine
CPU:           Q9950  (existing)
Mobo:          socket 775 Asus board  (existing)
Vid card:      upgrade to GTX470 (from Radeon 4850)
RAM:           add 4MB for total of 8MB max for board (1600, 99924)
OS:             create new boot disc running Win7 64  (new..currently XP)
HDD:           128GB SSD boot (new)
HDD:           Caviar black drives for media, etc.  (existing)
PSU:           620HX  (existing)
OPTION TWO:  Build new box
CPU:            i7 950 (pretty good price now)
Mobo:          Asus P6X58D Prem
Vid card:      GTX470
RAM:           12MB (1600, 99924, Corsair)
OS               Win7 64
HDD:           128GB SSD boot
HDD:           Caviar black drives for media, etc.  (existing)
PSU:           850HX
Questions:
- Overall, is the extra cost of Option Two worth it?  How much improvement would I expect?
- Is the GTX470 worth it relative to my existing Radeon 4850 board?
- Is the SSD worth it as a boot drive at $265?
- Is the larger PSU necessary?
- Any other thoughts on either configuration?
Thanks in advance for any feedback!
p.s.  I don't feel the "need" to build a new system, but am happy to do so if it Option 2 is a significant improvement.

Answer 1

Bill gave you the link to the PPBM5 Benchmark
The best performing Q9550 system ends up will a total time of 711 s and a RPI of 694.2 with 8 GB of RAM and a GTX 470. This means this system is nearly 7 times slower than the top performer, but even in comparison to my own system (195 s and RPI 154.1), which is old and has never been more than mediocre, it is 4.5 times slower.
These figures are of course not a guarantee that an upgrade of your existing system will be 4.5 times slower than my system, because a lot depends on the degree of tuning. Just notice that my system outperforms a number of 980X systems and systems with 24 GB memory, but it is indicative.
Regarding memory:
As you see from the benchmark results, there are quite a number of systems that successfully run with 24 GB. I do not know what brand and model of memory is installed in each of them, but names that come to mind are Corsair Dominator, G.Skill Ripjaws or Trident, Mushkin and OCZ. If you look on the QVL, realize that
a. ASUS does not make it a habit to update the list regularly,
b. ASUS does not test all kinds of memory, saying that is up to the memory manufacturer,
c. Manufacturers that appear on the list multiple times usually have compatible modules in the 4 G variant.
The benchmark does not give you 'real live' results on how your projects will perform, because we don't know what your projects will look like. There are too many styles of projects, to answer that question. Just consider a 3 minute music clip versus a 60 minute documentary versus a 2 hour wedding video. All requiring different effects, CC, transitions, audio, etc. and you can imagine no one can tell you what a configuration will give you in your situation. In general one can say that a 3 minute music clip is more dependant on CPU/GPU speed than on disk setup, while a 2 hour wedding movie relies more heavily on disk setup.
Hope this helps.