The AMD Spider platform: Series-7 chipset, Phenom CPU, HD38x0 GPU

THE PHENOM CPU – 4 CORES IS BETTER THAN TWO

When AMD moved from the Socket939 to Socket AM2 a lot of users were upset. There seemed not to be much of a difference between the Socket 939 and the AM2 CPU’s to warrant a change in socket. It was apparently a difficult decision for AMD to make this move but it was done with the future in mind. This is obvious when looking at the new AM2+ socket that is introduced with the Series-7 chipset. Older AM2 CPU’s will work fine in the AM2+ socket while new Phenom’s will work fine in the older AM2-sockets. All that happens is that the new features will not work. The next update to the socket will also be backward compatible with the current sockets making it possible to upgrade to a new motherboard without having to change CPU.

So what are the stand-out features of the Phenom?

First “True” Quad-Core Desktop processor
AMD really likes to tell everyone that unlike the current Quad-Core from Intel, which is 2 Dual-Core CPU’s put together, the Phenom is a true Quad-Core CPU built up from the ground. All cores, the memory controller and separate I/O interface communicate through a high performance crossbar switch.

Integrated memory controller
This is not a new feature but it is worth mentioning. The integrated memory controller can optimize memory performance both with matched and mismatched DIMMs. The physical address space has been increased to support up to 256 TB of memory.

Shared Third Level Cache
The shared L3 cache provides additional cache capacity; it provides a shorter average latency for cache and allows cores to rapidly share information without DRAM access. This reduces access latency.

HyperTransport 3.0
HT 3.0 has the potential to increase the I/O bandwidth to 5.2 GT/s. The raw bandwidth is up to 20.8 GB/s. The Phenom is of course backwards compatible with HT 1.0 and HT 2.0 although you get less bandwidth with them (up to 6.4 GB/s raw bandwidth for HT1.0 and 8.0 GB/s for HT2.0).

Cool’n Quiet 2.0
In these environmental conscious times it is nice to be able to have your CPU take it easy when the full power is not needed. In the Phenom AMD has updated Cool’n Quiet adding more features to lower idle power consumption and reduce fan noise. The processor has a C1E power state which activates when all the cores are inactive. It disconnects the HyperTransport link, places the memory in low-power mode and lowers the internal clocks.

A new feature called PSI (Processor Power Saving Indicator) helps reduce the amount of current fed to the processor. A new processor output can notify the processor voltage regulator that not as much current is needed. The voltage regulator can then reduce the number output phases to improve efficiency when the cores are idle.

These new features bring the Phenom in compliance with the new Energy Star 4.0 requirements.

Overall it sounds pretty cool, doesn’t it? Well – there is a bit of a problem though. First of all AMD is only bringing out a 2.2GHz (AMD Phenom 9500) and a 2.3 GHz (AMD Phenom 9600) part. You might wonder where the 2.4 Ghz Phenom (AMD Phenom 9700) is? Well, it turns out there is a problem with the first versions of the Phenoms. A bug has been found in the processor (actually in the L3 cache) which affects the stability of the CPU’s at some extreme cases. This bug is actually in all the current Phenom CPU’s but AMD thinks it only affects the 2.4+ GHz Phenoms. When the processor is running under a heavy work-load and some applications are run the processor crashes. AMD already has a bios-fix but that on the other hand can induce up to 10% speed-penalty. In fact, currently in the AMD Overdrive software you can opt to turn the bios-fix on/off depending on if you want to get the full speed but risk the bug or if you want to play it safe. AMD will of course fix this in the next revision of the chips but it still is a blow to them not even is able to get a 2.4 GHz part out.

During the event we had access to Spider-systems using the 2.4 GHz CPU and we could overclock it quite easily with the AMD Overdrive software to around 3.0 GHz so things are not as grim as they seem. Beginning next year we should hopefully see new faster Phenoms including FX-Phenoms that are clocked at 3.0 GHz. 

Performance

At the event we had access to some Phenom-systems and a limited number of benchmarks. The only benchmark that I could run on both the Phenom-system and my system at home was PCMark Vantage. Below is some of the sub-scores that might be of interest. As soon as I got my own Phenom at home more relevant benchmarks will be run.

Intel System: Intel Q6600@2.4GHz, 2 GB DDR3@1066 MHz, HD2900XT and HD3850 512 MB, 36 GB WD Raptor, Catalyst 7.10, Vista

Phenom System: Phenom 9700@2.4GHz, 2 GB DDR2@1066 MHz, single and dual HD3850 512 MB, 150 GB WD Raptor, unknown driver version, Vista