CPU clock vs memory speed effects on throughput

[Cobo_MI]

Was getting myself all psyched up to build my first PC, primarily for medium duty photo/video editing, no gaming use is planned. Here's what I'm planning:

ASUS P6X58D-E MB
Intel i7-930 2.8 GHz CPU
12GB Corsair Dominator RAM 1600 MHz
Zotac GTX 460 1GB graphics card (plan to update to Quadro 3800 or similar if I find Adobe Premiere Pro CS5 doesn't run fast enough)
Intel 80GB SSD for OS and apps
Separate 7200 RPM HDD for scratch disk

I'm a little nervous about compatibility with all the components (future graphics card fitting in the case, will I have enough cooling, etc.) and not really looking forward to the hassles of getting the latest drivers, loading all that stuff, etc.; but I am pretty sure I would be happy with it in the end. I'm not really interested in over-clocking, but I'm aware the components I chose above would allow it if I wanted to do it (might need upgrade to CPU cooler?).

Then, right before I clicked the checkout button on newegg.com, I checked Dell's website to see what specials they have. They're running a 2-day special on Studio XPS 9100 that saves around $500 compared to the price that I checked on Dell's website a couple of days ago. All told, for a couple hundred bucks more than the custom PC, I can get the Dell with:

Intel i7-960 3.2 GHz CPU
12GB RAM 1333 MHz
Zotac GTX 460 1GB graphics card (I would add this card myself to the Dell, with similar update plans as above)
7200 RPM HDD for OS and apps
Separate 7200 RPM HDD for scratch disk
2 year service

My question: The Dell machine has a processor running 15% faster than my custom PC, but the RAM speed of my custom PC is 20% faster than the Dell. Assume the same graphics card in both machines. For photo and video editing (Lightroom 3, Photoshop and Premiere Pro CS5), do you think one machine be significantly (> 10%) faster than the other?

 

[jsc]

The Dell machine should be a little faster.

A benchmark program would be able to tell, but I doubt if you could without a stopwatch.

 

[Herr_Koos]

With 12 GB of available RAM, I don't think the speed difference will be noticeable. You would benefit more from a faster processor.

I'm still edgy when it comes to buying pre-built machines though...

 

[LePhuronn]

The Dell spec would win out by a very small amount, but you'd need a benchmarking app to notice. But Dell machines generally suck (there will be a lot of corners cut in that build) so you'd be better off building yourself IMO

Also, the GTX 460 isn't officially supported by CS5 MPE, but you can hack it:
http://blog.krama.tv/hacking-adobe-premiere-cs5-to-enable-more-nvidia-cuda-cards/

But I'd strongly recommend getting the 2GB version of the GTX 460 from either Palit or Gainward for MPE in CUDA mode.