Ben,

With that i5-3550 CPU being only "limited"-overclockable, I would not go above a GTX 560 Ti or GTX 660 Ti for that system. You do want a good balance between the CPU and GPU in a video editing system.

And I agree with Harm that your disk setup needs some improvement.

 

Indeed, its a USB3 enclosure, ive been caught out by this before.

Then it depends on many varibles: the controller inside the enclosure and the controller on your motherboard. Some USB 3.0 setups can barely reach 100 MB/s in maximum sustainable transfer speed; other combinations can reach at least 150 MB/s.

Jim Simon wrote:

 

Is GPU used to play DSLR/AVCHD?

 

The GPU isn't used for any playback.  It helps with effects, scaling, color space, resolution and frame rate differences, but decoding for playback is always handled by the CPU.

That isn't exactly the case.  The graphics card still has to put the pixels on the screen and refresh the frame and I kid you not, I've seen PCs too slow to do that.  Remember all those emachines and HP's that shipped out in 2008 with the geforce 6150 onboard?  They cannot play youtube videos at full screen without chopping frames in half and skipping even with a high powered dual athlon chip and tons of RAM.  They can't play DVDs or video files above about 640x480 either.  All programs use the graphics card to some extent but playback of an unmodified video clip requires practically no calculations, just the OS telling the graphics card to create the separate graphics layer and put it on the screen.  In your case, with the 550TI, it's fast enough to play anything though.

I don't think external media limitations would result in individual dropped frames though so I can't figure out what's causing your problem.  That would cause temporary pauses when the buffer in memory runs out (on long videos) but not frames to drop.

Then it depends on many varibles: the controller inside the enclosure and the controller on your motherboard. Some USB 3.0 setups can barely reach 100 MB/s in maximum sustainable transfer speed; other combinations can reach at least 150 MB/s.

Luckily all actual Intel chipset-based controllers run at exactly the same speed since they're all exactly the same controller.  They're fast too.  Those dumpy aftermarket ones thrown on budget motherboards have severe performance issues though.  Some PCI-E controller cards don't do so well and some outperform the Intel versions so that's a real grab bag.

If you have a bunch of hard drives though, your PC probably has 1 SATAIII controller and 1 SATAII controller and that's it so the bandwidth is shared by all devices connected to them.  So because of that, I'd stick with USB3.0.  It's definitely not good enough for some sort of external RAID though, as it will hit the upper limit of speed really quickly and not perform at full speed.