Gaming? I ran Quake 4 updated with the Multi-threading patch.

23 Intel Core 2 Extreme QX6700 Preview

Apparently, the multi-threading boost is minimal, and the higher
clocked X6800 actually outperforms the QX6700 by 8%.

 

I tested out Video Rendering with Adobe Premiere on a 5 minute
30 seconds Video clip adorned with a huge tonne of effects.

15 Intel Core 2 Extreme QX6700 Preview

Even here, you can see that the 4 cores onboard are not fully
utilized from the task manager screenshot seen above.

QX6700
35Min 15Sec
X6800
32Min 58Sec

The X6800 actually finishes 2 Minutes 17 Seconds faster! That’s
6% faster than the QX6700. It’s time we throw in some multi-tasking
since we don’t like to sit on our bums to wait for tasks to finish before starting
on our next one.

 

I started the Video Rendering again, and then went on to run
Adobe Acrobat Professional to convert a 200 page Powerpoint file into PDF format.

(The conversion runs on the IDE Hard Disk while the Rendering takes place on
the SATA, to prevent Hard Disk bottleneck) Once that was started, it was time
to do some Quake 4 Fragging.

16 Intel Core 2 Extreme QX6700 Preview

QX6700
35Min 37Sec
X6800
36Min 39Sec

In such a scenario, the table was turned. The QX6700 was only
slightly affected (1% slowdown) and the whole video took 22
seconds longer to render. The X6800 on the other hand slows down by 12%,
taking 3Min 41Sec longer to render the whole video. The QX6700 is 3%
faster
than the X6800 is this particular Multi-tasking scenario.