After testing the new QX9650 we decided to check out the least expensive quad-core available now, the Q6600. This CPU comes in two flavors with B3 and G0 stepping. The G0 stepping is superior to B3 stepping, because it offers higher thermal specification. Its TCase temperature is 71°C vs 62°C, and offers better thermal protection and a 10W reduction in TDP, which is only 95W, compared to 105W with the old one. Overclockers should only select the G0-stepping version.
German Version available here.
ASUS Blitz Exterme (provided by ASUS)
Intel Core 2 Duo E6700 (provided by Intel)
Intel Core 2 Quad Q6600 (provided by Intel)
Intel Core 2 Quad QX6850 (provided by Intel)
Intel Core 2 Quad QX9650 (provided by Intel)
Scythe Andy Samurai Master (provided by Scythe-Europe)
Patriot 2GB Kit PC3-10666U PDC32G1333LLK (provided by Patriot)
CL7-7-7-20-CR2T up to 1.90V
AMD ATI Radeon X1950XTX (provided by AMD)
Silverstone Element SF50EF-Plus (provided by Silverstone)
Western Digital WD4000KD (provided by Ditech)
SilenX iXtrema Pro 14dB(A) (provided by PC-Cooling.at)
The Q6600 is only a 266MHz FSB part, so don't expect miracles while increasing the FSB. With 400MHz it was possible to boot into Windows, but stable operation was out of the question. Due to the fact you can't increase the CPU multiplayer you are stuck with the highest FSB you can get. In our case, we got 3420Mhz with FSB 380MHz, but it was not very stable.
For our benchmarks we reduced the FSB to 370 and got a nice 3330MHz which was stable in Prime test all the time. The Q6600 can take more voltage than its QX6850 counterpart, at least our samples did. VCore at 1.5000V did not cause any problems.
Please note that different BIOS revisions may give different results. All benches are done with AUTO settings, without altering any BIOS option besides CPU VCore and major CL settings. DDR3 speed is always 1066MHz, or as near to 1066MHz as possible.
Gordian Knot/XviD 1.1.3:
For our Gordian Knot testing we took a PAL episode of "Babylon 5" with a length of 41 minutes, 57 seconds and 8 frames.
We tried to "emulate" the most common usage of Gordian Knot:
1st: We have a perfect master, so we only de-interlace the content and resize it, without any other manipulations. We marked this as "fast."
2nd: You get bad mastering on many DVDs, especially "old" stuff or when the studios are in a hurry for the release. In this case you may want to improve the picture quality, which is done by filtering the content. You can choose from many filters for any purposes you can think of. We only used the most common "undot," "FluxSmooth" and "MSharpen." Of course, we also de-interlaced, filters were done before any resizing took place (which is slower). We marked this as "slow."
If you need more information about filters, we recommend reading the doom9.org forum
x264 is a H.264/AVC codec which supports four threads and is available for free. We used the same "slow" settings as XviD. H.264 gives you a huge advantage in compressing size, and you need much less bitrate to achieve the same or better quality compared to XviD. While the H.264/AVC is much more advanced compared to MPEG2 encoders, now the CPU-power is available to do the encoding in an acceptable time.
You can clearly see that a quad-core brings an massive advantage in encoding speed; the first pass seems to run on only two cores, but the second pass takes advantage of all four cores. With a quad-core you can nearly reach the speed of XivD, which can only use two cores for the time being.
The codec is open source, still in heavy development and you can grab it here.
We used the same episode for our MP3-testing. We don't recommend using MP3 for encoding, because AC3 can do the job better. The audio is almost 42 minutes long and it gives us approximately the length of most of an album. A measurement in seconds, as many sites use, is useless, because the differences are too small.
We used the built-in play/CPU ratio, which means the CPU is encoding x-times faster then the track-length. Fast memory does not play an important role here. They will be produced with any other L.A.M.E. version, because only LameMT can do more than one thread and take advantage of a second dice. We used this setting: lamemt --vbr-new -q 2 -V 2 -m j --strictly-enforce-ISO --resample 48.
A quad-core does not improve the speed, because it can only utilize two cores.
When buying a Q6600 you should use it with a board that can reduce the VCore in idle-mode, even when overclocked. As far as we know, only MSI's P35 Platinum can perform such a "miracle." All other boards won't reduce the VCore while the CPU is overclocked, which results in much higher power consuption. In a non-overclocked enviroment the Q6600 stays closer to the dual-core counterparts; when overclocked it uses 10-15W more than our old E6700 dual-core, an E6750 would increase the difference by another 14W.
Under load we see similar results as we did with the QX6850. While not or slightly overclocked the power-consumption is not that far off from an dual-core; the 3330MHz settings take another 40W.
If you need a quad-core now, the Q6600 is the least expensive one out there. It's not that efficient compared to the new Penryn-family, but it costs just the same as an E6850 and is only 60€ more expensive compared to an E6750. For the same price or approximately €220 to €230 you get four cores that can overclock all the way to 3.4GHz. It's also not an overclocker champion, but we didn't expect it to be.
For gamers and "normal" users, a quad core simply won't provide any advantage compared to any dual-core CPU, but in the near future some games will make use of them; for example, Microsoft Flight Simulator X already does.
We can only hope that quad core will become more important in 2008 and that there will be more games and applications to take advantage of it.
We recommend the G0 stepping over the B3 and you can check prices here.