Ever since the launch of the Bulldozer range and 9-series motherboards, the initial reviews of the processors were not encouraging to say the least.  Since then, AMD has decided to pull out of the enthusiast end of the CPU market, to focus in on the mainstream and low power processors.  This is despite the fact that Windows 7 (and Windows 8, natively) is now receiving updates so the operating system can understand the processor architecture a little better, and hopefully boost performance.  This gives a second wind to those owning (or thinking of owning) a Bulldozer based processor, and in turn, a 900-series motherboard.  With the updates in hand, today we are looking at five 990FX boards that may feature on the consumer or system builders’ radar. 

Read on for the full review.

When we first looked at the Opteron 6276, our time was limited and we were only able to run our virtualization, compression, encryption, and rendering benchmarks. Most servers capable of running 20 or more cores/threads target the virtualization market, so that's a logical area to benchmark. The other benchmarks either test a small part of the server workload (compression and encryption) or represent a niche (e.g. rendering), but we included those benchmarks for a simple reason: they gave us additional insight into the performance profile of the Interlagos Opteron, they were easy to run, and last but not least those users/readers that use such applications still benefit.

Back in 2008, however, we discussed the elements of a thorough server review. Our list of important areas to test included ERP, OLTP, OLAP, Web, and Collaborative/E-mail applications. Looking at our initial Interlagos review, several of these are missing in action, but much has changed since 2008. The exploding core counts have made other bottlenecks (memory, I/O) much harder to overcome, the web application that we used back in 2009 stopped scaling beyond 12 cores due to lock contention problems, the Exchange benchmark turned out to be an absolute nightmare to scale beyond 8 threads, and the only manageable OLTP test—Swingbench Calling Circle—needed an increasing number of SSDs to scale.

The ballooning core counts have steadily made it harder and even next to impossible to benchmark applications on native Linux or Windows. Thus, we reacted the same way most companies have reacted: we virtualized our benchmark applications. It's only with a hypervisor that these multi-core monsters make sense in most enterprises, but there are always exceptions. Since quite a few of our readers still like seeing "native" Linux and Windows benchmarks, not to mention quite a few ERP, OLTP, and OLAP servers are still running without any form of virtualization, we took the time to complete our previous review and give the Opteron Interlagos another chance.

The basic building block of Bulldozer is the dual-core module, pictured below. AMD wanted better performance than simple SMT (ala Hyper Threading) would allow but without resorting to full duplication of resources we get in a traditional dual core CPU. The result is a duplication of integer execution resources and L1 caches, but a sharing of the front end and FPU. AMD still refers to this module as being dual-core, although it's a departure from the more traditional definition of the word. In the early days of multi-core x86 processors, dual-core designs were simply two single core processors stuck on the same package. Today we still see simple duplication of identical cores in a single processor, but moving forward it's likely that we'll see more heterogenous multi-core systems. AMD's Bulldozer architecture may be unusual, but it challenges the conventional definition of a core in a way that we're probably going to face one way or another in the not too distant future.

A four-module, eight-core Bulldozer

The bigger issue with Bulldozer isn't one of core semantics, but rather how threads get scheduled on those cores. Ideally, threads with shared data sets would get scheduled on the same module, while threads that share no data would be scheduled on separate modules. The former allows more efficient use of a module's L2 cache, while the latter guarantees each thread has access to all of a module's resources when there's no tangible benefit to sharing.

This ideal scenario isn't how threads are scheduled on Bulldozer today. Instead of intelligent core/module scheduling based on the memory addresses touched by a thread, Windows 7 currently just schedules threads on Bulldozer in order. Starting from core 0 and going up to core 7 in an eight-core FX-8150, Windows 7 will schedule two threads on the first module, then move to the next module, etc... If the threads happen to be working on the same data, then Windows 7's scheduling approach makes sense. If the threads scheduled are working on different data sets however, Windows 7's current treatment of Bulldozer is suboptimal.

AMD and Microsoft have been working on a patch to Windows 7 that improves scheduling behavior on Bulldozer. The result are two hotfixes that should both be installed on Bulldozer systems. Read on for our take on what these hotfixes do to Bulldozer's Windows 7 performance.

AMD has been trailing Intel in the x86 performance space for years now. Ever since the introduction of the first Core 2 processors in 2006, AMD hasn't been able to recover and return to the heyday of the Athlon 64 and Athlon 64 X2. Instead the company has remained relevant by driving costs down and competing largely in the sub-$200 microprocessor space. AMD's ability to hold on was largely due to its more-cores-for-less strategy. Thanks to aggressive pricing on its triple and hexa-core parts, for users who needed tons of cores, AMD has been delivering a lot of value over the past couple of years.

Recently however Intel has been able to drive its per-core performance up with Sandy Bridge, where it's becoming increasingly difficult to recommend AMD alternatives with higher core counts. The heavily threaded desktop niche is tough to sell to, particularly when you force users to take a significant hit on single threaded performance in order to achieve value there. For a while now AMD has needed a brand new architecture, something that could lead to dominance in heavily threaded workloads while addressing its deficiencies in lightly threaded consumer workloads. After much waiting, we get that new architecture today. Bulldozer is here.

Read on for our full review!

AMD’s new Bulldozer-based CPUs are just around the corner. AMD has said the release of Zambezi CPUs will happen in Q3, which means any time from now. The latest word on the street suggests October release though. We know quite a lot about these CPUs already but there is at least one thing we didn't know until now and it may end up being a big thing in server market. AMD’s John Fruehe has published an interesting blog post where he reveals that AMD’s upcoming server CPUs, Operons, will feature a user-configurable TDP.  Read on for our overview on Bulldozer, thoughts on configurable TDP, and summary of AMD's future plans.

The past week shook up the whole computer industry with Intel’s announcement that a potential flaw in their Cougar Point chipset required a respin to fix. In the ensuing chaos, we’ve had quite a few reviews put on hold or pulled altogether as we await the revised chipset. We also have a few other items to discuss in regards to the mobility sector, so if you’re debating purchasing a new laptop/notebook vs. waiting for “fixed” hardware, we hope to shed some light on the situation.