AMD Phenom 9900 Overclocked

WE'VE SEEN a bit of Phenom's performance in the first partthis past Friday - how about pushing it a bit further?
This round, I tuned the Phenom 9900 - unlocked CPU, keep in mind - test setupas far as possible within an extra day for fully stable operations under bothWindows XP 32-bit and Vista 64-bit, and ran it against a fully tuned IntelQX9770 setup in an "AMD Best vs Intel Best" approach.
One may say that it's not fair since Intel's CPU is more expensive, however,on the other hand, the AMD one can't be bought at all for some time to come.
Both AMD and Intel configurations used dual Asus EAH3870 TOP cards in bothdefault and Crossfire modes, and identical Windows and Catalyst driver versions- so, as much of an apples-to-apples comparison as possible.
Besides the usual 32-bit benchmarks, the 64-bit run added CineBench10 andPovRay 3.7.
The Limits
This is where the Intel and AMD configurations differ in 32-bit and 64-bitmodes: Intel could do 4.27 GHz (multiplier 10, FSB1708) in both modes, but thevoltage needed for the 64-bit mode was 1.425 volts vs 1.40 volts for the 32-bitmode, if all tests were to complete.
When using Asetek Vapochill freeze cooling, the limits are 4.6 GHz FSB1840 at1.45 volts Vcpu in 32 bit mode, and 4.5 GHz FSB1800 at 1.4625 volt Vcpu in64-bit mode. However, this test run only uses the results obtainable on theusual high-end air or water cooling.
In the AMD case, the absolute limit on my setup with similar air or watercooling was 2.88 GHz (14 x FSB206) at 1.325 volts CPU in 32-bit mode, and 2.80GHz (14 x FSB200) at 1.337 volts CPU in 64-bit mode for a complete test run.Even then, though, the PCMark Vantage 64-bit run couldn't be completed.
The push to 1.35 and 1.363 volts didn't give any improvement except moreheat, so there was obviously no point trying harder.
I didn't really bother to push the memory too much here beyond reasonablelatency tuning, as CPU speed is the obvious focus of the story - Phenom has noproblems with memory performance, as in Sandra cases it still has a slight 10% -20% advantage in synthetic memory subsystem speed runs over the Intel offerings.
However, even after accounting for its L3 cache exclusivity, Phenom still hasonly one-third cacheable data size compared to the dual-die Yorkfield and thatseemingly more than neutralises its on-die memory controller advantage.
The results
The benchmark results - here they are:
3DMark06 default - Phenom 2880 Crossfire

3DMark06 default - Intel 4270 Crossfire

Povray 3.7 - Phenom 2800

CineBench - Phenom 2800 Crossfire

... and the other results (memory, CPU, Everest) in the table summary

As you can see, the differences are even greater when taking the overclockingheadroom into account. It is also very interesting to note the Crossfirescaling: on 2.88 GHz AMD, the total score goes up from 11096 to 15026, while onthe 4.27 GHz Intel, the Crossfire jump is from 13516 to 21496... so, it scalesbetter even percentage-wise on the X38 compared to AMD's latest and greatest790FX chipset?
The memory runs still stand out in AMD's favour, but obviously not for long -in just over two quarters, Bloomfield flavour of Nehalem will close that gap,too.
The Hope
Yeah, hope that this lopsided situation has a chance of balancing out by AMDradically improving either the speed yields of its K10, and/or improving thecore IPC by the time the 45 nm shrink is ready.
A combination of slightly lower clock-for-clock performance, and a thirdlower maximum clock headroom under similar conditions, gives us a very unevenmatch, where for every 1x of feather-weight Phenom performance, Intel'ssuperheavy-weight Yorkfield provides in excess of 1.7x using the currentbest-vs-best press sample comparisons.
Basically, they either sell the Phenom 9900 for not more than US$ 300 a piecewhen it comes out in March or April hopefully, or wave a 'magic wand' to somehowget 3.2 GHz or so speed within the 65 nm process and power envelope if keepingthe current microarchitecture intact.
Only at that speed will, in my mind right now, Phenom become somewhatcompetitive at the high end - and even that only in the US$ 500 - 700 per CPUprice bracket. Anything above to fight QX9770? Well, to charge a grand for aPhenom in early 2008, that one better be running at say 3.5 GHz or so.
Well, not all things are that somber. There is one short-term benefit for AMDhere - after looking at the today's 3Dmark06 comparison, it does seem to me thatthe perfect CrossFire platform for AMD GPU sales is there: the Intel X38 / X48platform running Yorkfield quad cores.
In fact, the QX9770 & X48 official - delayed - February shipping datesmatch nicely with AMD rollout of HD3870X2 dual-GPU cards. Put two of those ineach X48 mobo, CrossFire them with just one bridge cable, and you got aquad-core Yorkfield CPU feeding quad AMD GPU, in just two PCI-E x16 v2 slots!The "Intel Inside" Spider, anyone?
Now, that's a good one for AMD - for every such Intel enthusiast box, AMDwould sell some US$1000 or so worth of their high-end GPU card gear... not badat all, ain't it?
Well, could be better for their finances if they fixed the CPUs, since themargins are way better in that department - looks like Intel will continue torule here for another year, at least.