Reply to Brand new i5 Dell Latitude hugely under performing against old Dell Vostro

Both laptops have their own dedicated Traktor partition.

Old Dell Vostro 17", 2.2ghz dual core 3mb ddr2 ram, 32bit W7. Heavily optimised and a script I run (not currently running for the test) that closes background tasks such as wireless, spooler, etc.

vs.

Brand new Dell Latitude, core i5, 4gb ddr3 ram, 64bit W7. Heavily optimised, script is running for the test. Brand new install of Windows. Brand new everything.

The Vostro which is about 6 years old, with Traktor running and currently analysing hundreds of tracks, using the "DPC Latency Checker", is idling around 230ms and no big spikes. Traktor runs smoothly (unless I start dragging files from the other drive inside, but no biggy). No drop outs. No crashes. Everything ok.

New Latitude, with the script running and not even Traktor open, the "DPC Latency Checker" is idling around 1500ms!!! Its barely coming under 100ms. When I open Traktor and play a remix sample for a test and I move the volume fader on my VCI-100, it stutters visually and cuts out the audio very obviously. There looks to be some pattern with the latency checker, where it goes up to around 2000ms and then gradually comes down to just under 1000ms and then goes back up again. I cant screen shot, but its a very obvious pattern.

With a fresh restart and nothing running on either machine:

Vostro idles around 1-4% CPU usage and 644mb RAM
Latitude idles on 0% CPU usage with 684mb RAM.

When the Vostro does spike to around 90% CPU, the latency stays stable.
The Latitude does not spike CPU.

Any clues, at all?