Intel - Core 2 Extreme QX9650 review

Intel - Core 2 Extreme QX9650 review

Intel is releasing information about its next-generation Penryn Core 2 processors in carefully controlled stages. Penryn is the code name for the move from a 65nm process to 45nm, which dramatically reduces the size of the processor core. This reduces the cost of production and also frees up space on the core, so Intel is able to raise the quantity of L2 cache from 4MB to 6MB for each dual core Wolfdale package.

Penryn uses the same LGA775 package as Kentsfield and also shares the same layout, so a quad core processor uses two dual core chips, each with their own L2 cache. In the case of a quad core Yorkfield Penryn the amount of cache increases from 8MB to 12MB.

The other new feature with Penryn is the SSE4 instruction set. If you're running software that supports SSE3 or earlier then you shouldn't expect Penryn to show an advantage over Kentsfield. On the other hand, software such as the latest version of the DivX encoder that does support SSE4 should show Penryn in its best colours.

Intel told us about the architecture and fabrication process of Penryn early in 2007 and it has drip-fed us with information as part of its tick-tock process. In 2007 (a tick year) we'll see Penryn replacing Kentsfield with the new fabrication process on the same 1,333MHz FSB at similar speeds to Kentsfield. In 2008 - officially designated a tock year - Penryn will move to a 1,600MHz FSB and speeds will ramp up towards 4GHz.

We now have a sample of the 3.00GHz QX9650 quad-core Penryn which is directly comparable with the QX6850, so we can report on the performance of Penryn but we don't know anything about the pricing of the new processor.

Well, strictly speaking that's not true, as the QX9650 will be priced at $999 in quantities of 1,000 but that's always the case with the fastest CPU in any of Intel's ranges of desktop processors. Intel will tell us about pricing of the rest of the range in a week or two as the launch of QX9650 is presumably intended to spoil AMD's imminent launch of Phenom, but we can make some informed guesses.

The quad-core Q9550 will run at 2.83GHz with a price about half the QX9650, say £349. There will probably be a 2.66GHz Q9450 priced around the £199 mark and maybe a Q9300 that runs at 2.5GHz which will be somewhat cheaper.

Dual core models will be more relevant to the man in the street so the 3.16GHz E8500 may well be the gaming processor of choice for less than £200. We expect the 3.0GHz E8400 to cost close to £100 and then there will be cheaper, slower models such as a 2.83GHz E8300 and a 2.66GHz E8200.

But that's all guesswork.

We compared the QX9650 with a QX6850 which both run at 3.00GHz on a 1,333MHz FSB using an Asus Maximus Formula SE motherboard with X38 chipset and 2GB of fast DDR2 memory on Windows XP SP2.

In PCMark05 there was near-identical performance from both processors so we don't expect that Penryn is going to cause a revolution, however it showed a small advantage in video recoding with Nero 8 and a decent seven percent saving in time when we used the SSE4-enabled DivX 6.7.

Core 2 Duo E6700

Intel Core 2 Duo E6700

Intel is on a roll after the launch of Core 2 Duo E6700 in July 2006 and here we are, a mere four months later, with the launch of the quad core Core 2 Extreme QX6700 which was codename Kentsfield during development.

No doubt when Intel releases non-Extreme versions of this processor they will be called Core 2 Quadro or Quattro or something to reflect the four cores, provided it can find a name that hasn't been snapped up by Nvidia for professional graphics cards or Audi for four wheel drive cars.

In essence Intel has shoehorned a pair of Core 2 Duo processors on to a single LGA775 die, so the quad core runs on the same 1,066MHz Front Side Bus as Core 2 Duo and is fabricated on a 65nm process. There is 4MB of L2 cache for each pair of cores, so that's a total of 8MB of cache, and the core speed is similar to Core 2 Duo.

Core 2 Duo E6700 runs at 2.66GHz and has a TDP (Thermal Design Power) of 65W while the Core 2 Duo Extreme X6800 runs at 2.963GHz and has a TDP of 75W. By contrast the quad core Core 2 Extreme QX6700 runs at 2.66GHz and has a TDP of 130W so it truly is a pair of E6700 CPUs in a single processor socket. Let's not lose sight of the fact that the final versions of dual core Pentium 4 had a similar heat profile, so the technology to keep the processor cool is well established.

The Intel Press kit consisted of a QX6700 processor, a heatsink and a D975XBX2 motherboard with a Beta BIOS. Although the 975X chipset supports both Core 2 Duo and Kentsfield, it isn't necessarily the case that every 975X motherboard will support Kentsfield, so you need to check that your motherboard is 'validated for quad core'.

We understand that the differences between a 'good' motherboard and a 'bad' one come down to power regulation hardware. We laid the D975XBX2 next to a D975XBX and were unable to see any differences, but were told that the new board supports DDR2-800 memory and has enhanced audio control. Once we'd finished testing we played mix and match by plugging the quad core into the old D975XBX and it performed perfectly.

The move from a single core processor to dual core was like the difference between night and day, as you suddenly find that burning a CD or encoding MP3s doesn't make your whole PC freeze solid.

The move to quad core is far less dramatic as there is a limit to the number of applications that you can run simultaneously, but even so there's Windows in the background, your e-mail agent, anti-virus, anti-spyware, the music you're playing, your Internet browser, Word and Excel. By contrast an intensive 3D game is unlikely to use all of the abilities of the processor as very few games are threaded for multi-processor hardware.

We ran POV-Ray rendering benchmark on the Core 2 Extreme QX6700 as the 3.7 Beta has the facility to run on a single core or on all available cores. On a single core the test took 10 minutes 4 seconds, which is fairly swift, but when we switched to all four cores the test flashed past in 2 minutes 29 seconds.

Clearly the quad core hardware works, and when we ran PCMark05 back-to-back with the Core 2 Duo E6700 (same clock speed, half the cores) we found that the quad core got 8,150 marks and the dual core scored 6,879 marks overall, while the CPU elements of the test also favoured the quad core at 8,433 marks compared to 6,715 marks.

To our mind that accurately reflects the fact that most of us have no need for a quad core processor most of the time, but when you start to make your PC work for its living the extra cores pay dividends.
Intel - Core 2 Extreme QX6700 features - Verdict

In a few years' time we'll be amazed that there was an era when people had to make do with fewer than eight processor cores. The Intel Core 2 Extreme QX6700 is a significant step along the way to processing Nirvana and, although it costs a small fortune, we're very happy that its time has come.