CPU usage
We set off by checking whether frame rates were dropped in the Battlefield 2 Demo after we'd enabled various software and X-Fi audio modes – and they weren't.
So, getting extremely high-tech, we fired up the most venerable of audio players, Winamp 5, and compared some MP3 playback through the X-Fi and through an AC97-based onboard solution – an ASUS A8N SLI Deluxe motherboard with an Athlon 64 Winchester at 2.55GHz. The ASUS's onboard sound is pretty good as far as AC97 goes, but isn't half as easy to set up as the X-Fi.
So, with Task Manager running, what did we see?
Above we have the X-Fi's results. There's an occasional blip in CPU usage, we think from disk access. The small peak in the graph is where we disabled the 3D Crystallizer. This causes a popup to appear on screen - hence the increase in CPU usage. In the lead up to disabling 3D Crystallizer, there was no change in the pattern of CPU usage. So, the X-Fi has no significant impact on CPU usage, with or without audio enhancement.
The AC97- based solution, above, shows the same four per cent jumps in CPU usage from disk access, plus some much higher peaks. These are at roughly consistent intervals and we identified a "System" process as the cause. We replicated this several times, with and without background applications running, and we able to attribute this to playback through the AC97 device. X-Fi wins for CPU usage, then.
Admittedly, not the height of scientific study here but the simple graphing of CPU usage shows us that X-Fi trumps AC97.
