Technology III - Virtualisation, L3-Cache, HTT 3.0
The virtualisation functionality integrated in the Phenom processor has also received a notable performance boost . Now, operating systems in virtual environments can interact directly with the hypervisor, the management software for virtual machines. This reduces the switching times between the hypervisor and the virtual machines.
This functionality is already found in the Barcelona-based Opteron processors of the server segment. Since both processors, i.e. the Phenom and the new Opteron, use the same core design, this function can now be used on the desktop without limitation as well.
As a result of AMD's decision to use a single-die design for its quad-core processor, the chipmaker is able to let all four cores share a common L3 cache. In other words, AMD is implementing an L3 cache. Each of the four processor cores possesses its own 512 kB L2 cache. Additionally, all cores have access to the same data pool through the 2 MB of L3 cache . This leads to an additional increase in performance.
Additionally, the L3 cache acts as a write buffer for the system memory, which also brings a small performance increase with it.
Unlike the Athlon 64 X2, the Phenom processor no longer uses the Hypertransport 2.0 interface. Instead, AMD pairs it with the faster Hypertransport 3.0 , which increases the available bandwidth to 20.8 GB/s and can result in better 3D performance. This is an especially important factor when a multi-card Crossfire setup is used.
Hypertransport versions and their respective bandwidths:
- Version 1.0: 6.4 GB/s, 1600 MHz
- Version 2.0: 8.0 GB/s, 2000 MHz
- Version 3.0: 20.8 GB/s, 3600 MHz
Since the Hypertransport protocol is downward compatible, users will be able to plug the Phenom into older AM2 socket boards as well as the new AM2+ generation.