AMD Quad FX slaughtered by a single Intel CPU

All the reviews are in for AMD's new "4x4" Quad FX dual CPU platform and it loses nearly every single real world benchmark to a single Intel CPU while consuming more than twice the electricity.  We basically see two FX-74 3.
Written by George Ou, Contributor

All the reviews are in for AMD's new "4x4" Quad FX dual CPU platform and it loses nearly every single real world benchmark to a single Intel CPU while consuming more than twice the electricity.  We basically see two FX-74 3.0 GHz processors getting slaughtered by a single Intel QX6700 2.66 GHz quad core processor!  Ironically, three of the four benchmark sites I link to give such contradictory glowing conclusions for the Quad FX in spite of their own data showing AMD being slaughter that Baghdad Bob would be proud.  Here are the four reviews of which only TomsHardware had a realistic conclusion that matched their actual data.

From highly optimized multi-core applications like 3D rendering and Video encoding to single threaded applications like games the AMD Quad FX either lost by a little or it lost by a lot.  AMD had its best showing in 3D Studio Max by winning one of three rendering tests by a razor thin 1% margin though it still lost every other rendering test in 3D Studio Max.  The only victory the AMD Quad FX managed to squeeze out was a razor thin victory in the synthetic benchmark CineBench though this wasn't reflected in any real world applications.  On other benchmarks like Photoshop CS, video encoders, audio encoders, and games, AMD continued to get stomped by trailing 10 to 40 percent.  The only good news for AMD was that it managed to narrow the gap in multithreaded applications though it's far from caught up in over all performance.  [Update 12/1/2006 - Here are some Vista RC2 Ultimate edition benchmarks that fair better for AMD because of Vista's support for NUMA (Non-Unified Memory Architecture) that AMD uses.  It's still not enough to catch up to the Intel QX6700 quad core system]

If we factor in overclocking, the AMD FX-74 is basically at the end of the line.  TomsHardware said that there was "virtually no overclocking margins for the FX-74 top model" and HOT Hardware said that they managed to squeeze out a pathetic 7.1% increase.  AMD has hit a thermal brick wall with their 90 nm part while Intel's Core 2 overclocks like a dream.  The top of the line Intel QX6700 has an amazing 40% overclocking margin allowing the reining performance champ to gain an extra 40% performance.  Falcon Northwest for example sells a QX6700 factory overclocked and PC guaranteed at 3.73 GHz!  The fact that Intel QX6700 beats the Quad FX at a substantially lower clock rate and the fact that the QX6700 can clock significantly higher than Quad FX means that Intel QX6700 owners will enjoy a 40 to 80 percent performance advantage when they unleash their CPU.

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From a power consumption standpoint, every benchmark showed the Quad FX PC drawing more than double the power of an Intel-based PC with the QX6700 quad core CPU.  The difference on TomsHardware wasn't as bad for AMD but the results were seriously flawed since they used the same 1000 watt power supply for both Intel and AMD arguing that it was more fair.  Using the 1000 watt power supply was the wrong decision since no one should ever be putting in a 1000 watt power supply when an efficient Active PFC 360 watt power supply is already over kill for the Intel-based PC that peaks at 260 watts.  It's not Intel's fault that AMD forces you to use a massive power supply for their Quad FX platform so why would you force that decision on the Intel PC?

Using the same expensive 1000 watt power supply for an Intel single socket PC is grossly irresponsible because you'd be throwing away a lot of energy (and money) in the form of heat which requires you to use even more energy on your AC system.  TomsHardware did did the right thing by tweaking the power management features which allowed the AMD system to come closer to Intel on idle power consumption, but the power supply decision was stupid and unrealistic.  From a power consumption standpoint, the AMD Quad FX is a the Hummer of PCs without any of the performance benefits.  It just senselessly guzzles power while delivering inferior performance on every application. 

From a price standpoint, the Quad FX is priced competitively at $1000 for a pair of FX-74 dual core CPUs while a single Intel QX6700 quad core CPU costs $1000.  The QX6700 is in high demand so street prices are currently hovering around $1100.  The problem with the AMD Quad FX is that you'll need a significantly more expensive motherboard that supports two CPU sockets.  At present time, the only Quad FX motherboard available is the ASUS L1N64-SLI WS dual socket mother board which lists for $350 [UPDATE 12:50 AM - $480 is what most sites are quoting which probably sounds closer to what a dual socket motherboard costs].  The motherboard isn't too bad if it's actually $350 since it gives you 12 SATA ports, dual Gigabit LAN, 10 USB 2.0, and four PCI Express slots two of which are x16 graphics slots.  You'll have to ask yourself if you actually need 12 SATA hard drives and two graphics cards.  I should remind people that anyone who bought a thousand dollar SLI pair of graphics cards two months ago are kicking themselves now because a single NVIDIA 8800 GTX graphics adapter today offers superior performance while costing far less.  Sure you can go with two 8800 GTX controllers but the current games really won't deliver that much more bang and prices will only go down in the future while performance goes up.  There's also nothing to prevent you from getting two graphics cards with an Intel based system.  <next>

Two weeks ago AMD invited me to their San Francisco preview of the Quad FX platform though I couldn't get much on specifics on pricing, benchmarks, and other specifics.  When I asked AMD about the massive power consumption, they said that the enthusiast doesn't care about power consumption which seems kind of hypocritical every time I drive down the freeway and and I see the AMD sign criticizing Intel for wasting billions of dollars in energy.  I don't know a single PC enthusiast that likes extra heat and noise when they're not getting any performance advantage.  In response to my question if this is hypocritical or not, AMD told me that their mainstream lower end PCs have better idle performance specifications than Intel because of Cool'n'Quiet.

There is some evidence to suggest this is true though it's hard to compare fairly since you're comparing lower performing AMD CPUs to higher performance Core 2 Intel CPUs that have voltages set conservatively to high.  There's plenty of evidence to suggest that there is a lot more room to drop the voltage on Intel Core 2 CPUs when they're operating in the sub 2.4 GHz range while maintaining stability.  MacBook owners know they can under-volt their Intel-based MacBooks to prevent burning their legs if they rest their notebook on their laps and gain battery life.  There are PC motherboards that can dynamically adjust voltages up and down along with clock speeds and the Intel Core 2 CPUs just have that much more room to dynamically clock up or down.

I suspect the only reason Intel doesn't offer 45 watt 2.4 GHz desktop Core 2 parts is because they don't want to step on their successful mobile product line which uses the same Core 2 architecture.  While AMD has their "EE" (energy efficiency) line of processors that can go as low as 35 watt TDP, they are no where to be found in the retail or mail order channel so it's not really fair to compare something you can't actually acquire.

I spoke with AMD today by phone to ask them about the poor performance results on all of these different benchmarking sites and they tried to direct my attention to the platform.  AMD points out that this will usher in a new era of dual socket desktop PC computing though companies like Dell and Apple have been selling dual socket Intel PCs for months.  AMD points out that this is for the desktop market rather than the workstation or server market though I still don't understand what difference it makes other than the name we give it.

The one discernible difference is that the AMD dual socket Quad FX platform doesn't require you to buy server class fully buffered error correcting memory.  AMD also points out that Quad FX will be upgradeable to 8 cores by the middle of next year when AMD releases their Quad Core processor.  The problem for AMD is that you can go 8 core TODAY with a dual socket server/workstation Intel solution using Intel 5300 series quad core processors.  As for upgrading to eight cores, does anyone really want to throw away two FX-74 processors 7 months from now?  If you really want AMD's quad core CPU, you'll probably want a new motherboard with the new HyperTransport 3.0 with double the clock speed so I can't really see any upgrade advantage for the current Quad FX platform.

The bottom line is that AMD has delivered a Frankenstein of a solution that guzzles a ton of power while delivering inferior performance.  I just don't know of any other way to describe the AMD Quad FX platform.  While AMD has superficially (not on a clock-for-clock or overclocking potential basis) closed some of the performance gap, there is just no way for any sensible person other than diehard AMD fans to love the Quad FX.

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