Details on AMD Bulldozer: Opterons to Feature Configurable TDP

Final Thoughts

In the last few years, AMD hasn't really been able to fight against Intel in the high-end CPU market. Pretty much since the release of the Nehalem microarchitecture in late 2008, Intel has held the crown of fastest CPUs and AMD has only been the best option for budget builds. Bulldozer has suffered from delays and recently AMD delayed it even more because the performance didn't meet their expectations. However, Bulldozer could have the potential to shake Intel's position in other than the budget CPU market.

According to leaked product positioning slides, Zambezi is aimed to fight against Intel's Core i5 and i7 lineups. Zambezi will feature up to eight cores, which is twice as many as i7-2600(K)'s four cores. AMD said that they won't join the Hyper-Threading club and they will deliver as many physical cores as Intel delivers physical and virtual cores combined. It looks like AMD is keeping their word, though they're only delivering half as many "FP/SSE cores". Intel will probably still provide the best single-threaded performance but AMDs aggressive approach with many physcial cores may bring them the trophy of best multi-threaded performance. We shall hopefully see this very soon.  

In the server market, AMD's role is a lot more complex. For some HPC applications, AMD offers the best performance at a much lower price. In the midrange, AMD based servers offer more cores (quad-socket) and (in most cases) higher performance for a relatively small price premium over the typical dual-socket Xeon servers. At the same time, if your applications cannot make good use of all those cores, dual-socket Xeon servers can offer a better performance/watt ratio and lower response times. In the high end, Intel Xeon E7 completely dominates, and AMD has left this market for now. In the low power market, Intel's low power Xeons offer a better performance/watt and AMD can only compete when every dollar counts. In most cases, the price of the server CPU is less important in the grand TCO scheme.

In other words, AMD really needs a server CPU with a much higher performance per core and a better performance/watt ratio. TDP Power Cap or configurable TDP helps AMD's server CPUs keep the electricity bill down by avoiding "bursty" power usage. At the same time, with their implementation, TDP Power Cap should have little effect on the real world (not pure throughput benchmarking) performance if you do not lower the TDP too much. We won't be sure until we have measured it, but it looks like a big step in the right direction: lower TCO and more predictable power usage without a (large) performance penalty.

AMD's Future Plans

Bulldozer will make its way to mainstream CPUs in 2012. Llano's successor, Trinity, will feature up to four next-generation Bulldozer cores. Next-generation (NG) in this context appears to mean that AMD will tweak the architecture because the CPUs will still be manufactured using 32nm SOI. Zambezi's successor, Komodo, will again increase the core count and make it up to 10.

As for the server market, AMD's approach will be a bit more aggressive. AMD will again increase the amount of cores to up to 20 NG Bulldozer cores. Valencia's successor will be 10-core Sepang and Interlagos' will be 20-core Terramar. The server CPUs will also feature PCIe 3.0 support.

Krishna and Wichita will also replace AMD's current Ontario and Zacate APUs. There will be a die shrink from 40nm to 28nm so at this point, Krishna and Wichita look the most interesting from the 2nd gen Fusion lineup. Doubling the cores should yield a nice performance boost in heavily threaded scendarios, though single-threaded performance is still a sore spot for Bobcat compared to other architectures.