Monday, November 26, 2007
Phenom is Here!
Well, there it is! The above photo is an actual die of the new Phenom CPU from AMD. Over 600 million transistors packed into a mere 285 square milimeters, containing four discrete processing cores, each with its own dedicated 512 KB L2 cache and a new shared 2 MB L3 cache.
This new CPU incorporates many new technologies and improvements over the Athlon 64x2 processors - A new instruction set, SSE4a; an advanced memory prefetcher that can load data directly from RAM to the L1 cache; improved branch prediction logic with a sideband stack counter to reduce load on the CPU cores: improved virtualization functionality to boost the performance of multiple Operating Systems running in a virtual Environment; a new shared L3 cache; a new Hypertransport 3.0 bus running at 3.2 ghz; and a new Cool 'n' Quiet 2.0 power saving feature that allows the reduction of the core clock and voltages for individual cores.
One of the niftiest things about this new processor, is something you don't usually see in a new CPU architecture - Backwards compatibility. While this CPU is designed for use in the new socket AM2+ motherboards with the new 3200 mhz Hypertransport 3.0, it will also work in the older AM2 sockets using Hypertranport 2.0 (2000 mhz) and 1.0 (1600 mhz). That means current users with AM2 motherboards may be able to upgrade to quad core, with nothing more than a BIOS update.
While all of us AMD fans out here were really hoping for a Core 2 'killer', that would dominate the performance benchmarks much like the original Athlon XP and Athlon 64 totally dominated the performance arena from 2002-2006, alas, such was not the case. Instead of leapfrogging ahead, they have basically just caught up. Right now the performance is about equal, clock for clock, between the Core 2 quad and the Phenom. But since the Phenom is priced below the Intel chips, that does make them a better buy right now.
One reassuring item in AMD's favor is that the new CPU's seem to overclock quite well. In fact, for the first time ever a CPU manufacturer is offering their own overclocking utility, called AMD Overdrive, which accesses the CPU directly, letting the user adjust the base clock, multiplier, core voltage and memory timings from within windows. Early results are very promising, allowing the 2.4 Ghz CPU to easily reach 3.0 Ghz on air cooling. I have a feeling we will see Phenom models with larger caches running at 3.0 Ghz by summer, providing enthusiasts with a viable lower cost option to the Intel Extreme QX6850, that provides comparable performance levels.
2008 is certainly looking to be an interesting year!