We used the latest version of TMPEG 4.5.2.255 and DivX 6.8, and encoded a 980MB 720x480px 4-8k VBR MPEG-2 video with 48KHz PCM stereo sound into a 320x240px DivX under the "Mobile" profile with a single pass, with 112kbps LAME .MP3 joint stereo sound. This included setting multi-threading and SSE2/4 where possible in the DivX settings.
TMPEG 4.0 Xpress
Source File: 980MB 4-8k VBR MPEG-2 PCM Stereo. Encoding: Divx 6.8 Mobile Profile, 720x480 to 320x240
Again the Core i7s burn through video encoding and in a clock for clock race they are 18 percent faster than Penryn with SMT enabled. Without Hyper Threading on there's only a very little three percent loss of performance. Turning down the QPI bus does very little here, as does disabling SMT, Turbo mode and dropping down to dual channel memory - all of which perform within a few seconds of each other and are between three to four percent slower than the all-on i7 965.
With the Core i7 965 limited to single channel DDR3, it still manages to outperform the i7 940 surprisingly, but both are 12-to-13 percent slower than the i7 965. Between the Q9550 and the i7 920 which carry a loosely similar price, the latter is ten percent faster for a lower price tag, while clock for clock the Q9450 is 13 percent slower.
Sony Vegas Movie Studio is an industry leading movie making application that offers support for a large variety of video formats. It can handle the latest multi-channel audio and high-definition content, even including AVCHD and HDV. Further features include mixing and editing, video composite creating and video restoration among others. As a highly threaded application it makes great use of multi-core processors.
Here we use the free version: Platinum 8, to transcode a 720x480px 945MB raw .MTS with PCM audio into a 720x480px WMV9 at VBR90, with 5.1 channel 44.1KHz 64Kbps WMA audio.
Yet again the Core i7 turns out to be an encoding behemoth, with them all stretching out a significant performance lead over even the fastest Penryn CPUs by at least 40 seconds.
Clock for clock there's a 22 percent performance advantage for the Core i7 965 versus the QX9770, while the 920 has a 17 percent advantage over the similarly priced Q9550 and a 21 percent advantage over a clock to clock matched Q9450.
Again Turbo mode and QPI do little for Sony Vegas - there's just a one or two percent difference in performance. However, disabling SMT drops the performance considerable seven percent or a whole minute in round terms. Dual channel memory again provides a solid performance but single channel causes a 12 percent performance drop, although this single channel DDR3 1,066MHz is still faster than the same clocked QX9770 with dual channel DDR3 at 1,600MHz.