CPU Guide

"Here Be Dragons" - AMD Phenom II

"Here Be Dragons" - AMD Phenom II

What's New in the Phenom II?

What's New in the Phenom II?

The Phenom II will initially launch with just two models, the Phenom II X4 940 and the 920, at 3.0GHz and 2.8GHz respectively. That's already 200MHz higher than the 2.6GHz Phenom X4 9950. Do the model names sound suspiciously like the Core i7 naming scheme to you? In fact, AMD's own marketing documents names the two as direct competitors in its comparison, the caveat being that the Phenom II X4 940 was part of the Dragon platform facing off against the complete Intel Core i7 platform including motherboard, GPU and hard drive.

Core and Power Efficiency Enhancements

As you can see, there aren't that many differences between the Phenom and the Phenom II. Notably, the L3 cache has gone up on the Phenom II, with a total of 6MB that is three times the amount on the Phenom and also brings it closer to the 8MB found on the Core i7. While AMD's move to AM3 and DDR3 seems to be imminent, it's not happening yet with these two Phenom II models, as they remain at DDR2-1066, which if you look at the bright side, these memory modules should be going for a song nowadays.

AMD however plans to support up to DDR3-1333 on the AM3 Phenom II, so if you're holding out till then, stock up on those memory sticks. The HT link frequency however is slightly slower at 1.8GHz when compared to the 2.0GHz link we saw on the higher-end first generation Phenoms, giving the new Phenom II a HT bandwidth of 3.6 GT/s. However we believe AMD has another faster model that will be unleashed later and this would likely boast a higher HT frequency.

Another touted feature is AMD's Cool'n'Quiet technology, which has been upgraded to version 3.0 on the Phenom II. While the Phenom II remains at a TDP of 125W similar to the higher-end Phenoms, AMD claims that one will see up to 50% improvement in idle and low load power consumption over the Phenom. That's something that we'll test for ourselves later in this review.

A part of this is undoubtedly due to the 45nm die shrink while the rest is due to the Phenom II having more power 'steps' or performance states which can adjust dynamically to the current usage. Additionally, AMD's Smart Fetch feature allows unused cores to go into a 'halt' state where power draw is then reduced, with the data from that core's L1 and L2 cache saved into the shared L3 cache.

AMD's Upgrade Roadmap

Value is a big part of the message that AMD hopes to present with its Dragon platform and that's certainly true if you consider that AMD has mapped an upgrade path for those already on the AMD platform. The Phenom II itself comes in the AM2+ package that ensures that it will fit on most current motherboards with nothing more than a BIOS update. AMD recommends the 790GX chipset in particular, since this newer chipset has both the recent SB750 Southbridge and support for the company's Advanced Clock Calibration feature that allows the Phenom/Phenom II to be pushed further in terms of overclocking.

Also, as the roadmap above shows, when the shift to AM3 and DDR3 memory occurs later this year, there's also some compatibility remaining since AM3 processors are backwards compatible with AM2+ motherboards so you can opt to wait for the AM3 versions. In short, AMD is hoping this upgrade plan will be more palatable than the one offered by Intel with its new Core i7 platform, with its different sockets (LGA 1366 and 1156) and its higher upfront cost. In these troubled times, AMD's approach certainly has its appeals on our wallets.

Finally, here's a summary of the specifications for the AMD and Intel quad-core processors available now:-

Current AMD/Intel Processors
Processor Name Core i7 AMD Phenom< II X4 AMD Phenom Core 2 Extreme / Quad (45nm)
Processor Model i7-965 Extreme Edition, i7-940, i7-920 940, 920 9950 'Black Edition, 9850 'Black Edition', 9850, 9750, 9650, 9550 QX9775, QX9770, Q9650, Q9550, Q9450, Q9400, Q9300
Processor Frequency 3.2GHz, 2.93GHz, 2.66GHz 3.0GHz, 2.8GHz 2.2GHz - 2.6GHz 2.5GHz - 3.2GHz
No. of Cores 4 4 4 4
Front Side Bus (MHz) - - - 1333
HyperTransport Bus / QuickPath Interconnect 6.4GT/sec for i7-965 EE, 4.8GT/sec for i7-940, i7-920 1.8GHz 2.0GHz (9950, 9850 only), 1.8GHz -
L1 Cache (data + instruction) (32KB + 32KB) x 4 (64KB + 64KB) x 4 (64KB + 64KB) x 4 (32KB + 32KB) x 4
L2 Cache 256KB x 4 512KB x 4 512KB x 4 6MB x 2, 3MB x 2 (Q9300 & Q9400 only)
L3 Cache 8MB 6MB 2MB -
Memory Controller Integrated Triple Channel (up to DDR3-1066) Integrated Dual Channel (up to DDR2-1066) Integrated Dual Channel (up to DDR2-1066) External - Chipset Dependent
TDP (W) 130 125 95 - 125 95 - 130
Instruction Set Support MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2 MMX, SSE, SSE2, SSE3, SSE4a MMX, SSE, SSE2, SSE3, SSE4a MMX, SSE, SSE2, SSE3, SSSE3, SSSE4.1
Execute Disable Bit Yes Yes Yes Yes
Intel EM64T / AMD64 Yes Yes Yes Yes
Enhanced Intel SpeedStep Technology (EIST) / AMD Cool 'n' Quiet Yes Yes Yes Yes
Virtualization Technology Yes (Enhanced) Yes Yes Yes (Enhanced)
Packaging LGA1366 AM2+ AM2+ LGA775
Process Technology 45nm 45nm SOI 65nm SOI 45nm
Processor Codename Bloomfield Deneb Windsor Yorkfield
Die Size 263mm² 258mm² 285mm² 214mm²
No. of Transistors 731 million 758 million 450 million 820 million