Bulldozer prototype suggests AMD shooting for Sandy Bridge performance

Another Bulldozer engineering sample has been benchmarked in the wild, turning …

Chris Foresman – Jul 13, 2011 5:00 pm | 56

Editor’s note: The original source of the information that Donanim Haber published this week on the alleged AMD Bulldozer engineering sample has admitted that the information was faked. Many sites were fooled by this information, including Ars, particularly because the results were plausible and fit the information we had about Bulldozer so far. Editor Emeritus Jon Stokes vetted our analysis, also believing the information to be true. Bulldozer CPUs are expected to be released in the next couple months, so we should have real results we can look at soon. However, we stand by our analysis, namely that Bulldozer will need to mainly compete on price and not raw performance.

Original story: AMD’s Bulldozer processor architecture still hasn’t formally launched, but Donanim Haber got a hold of a recent engineering sample with benchmarked speeds that come close to Intel’s current Sandy Bridge CPUs. With the ability to run limited cores at up to 4.2GHz, it could potentially outperform comparable Intel hardware at certain workloads. Still, AMD’s “1.5 core” SMT approach may offer “good enough” performance, which could have wide appeal if the price is right.

An earlier engineering sample leaked back in March ran at a measly 1.8GHz, and the widely variable results made it hard to draw any usable conclusions. The latest sample uncovered by Donanim Haber, identified as a FX-8130P, has a base clockspeed of 3.2GHz. With all four Bulldozer “1.5 core” modules running, the processor can “turbo boost” its speed up to 3.6GHz. When only half of its modules’ hardware is active, however, it can crank the speed up to 4.2GHz.

Stuffed in an AM3 socket-equipped motherboard and running alongside an NVIDA GTX 580 GPU, the Bulldozer-based processor turned in a respectable 3DMark 11 score of 6265. Its physics score, which is largely CPU dependent, is 7487. That puts its performance between Intel’s latest quad-core, Sandy Bridge-based Core i5-2500K (6667) and Core i7-2600K (8152), according to recent benchmarks run by Tom’s Hardware.

The FX-8130P’s PCMark 7 score, on the other hand, is just 3045. That doesn’t even beat AMD’s own A8-3850 clocked at 2.9GHz (3575), let alone Intel’s Sandy Bridge parts.

As we noted in the past, AMD’s approach with Bulldozer makes its performance highly workload-dependent. For many common server applications, which largely depend on integer operations, Bulldozer’s doubled-up ALU hardware should perform handsomely. And its lower transistor count and ability to more finely control power distribution among its various blocks means it could offer some performance/watt advantages.

Bulldozer should be launching around the same time as Intel’s Sandy Bridge-based Xeons. There’s simply no way that Bulldozer will be able to compete with those processors in raw performance when it can just barely keep up with quad-core, “consumer grade” parts. Still, if the final hardware is priced right and saves a few watts per server, it could prove to be a success.

On the other hand, Intel’s Ivy Bridge desktop processors should be coming out sometime in the next 6-12 months. Again, Bulldozer’s 32nm design simply won’t be able to compete with the performance of Ivy Bridge’s 22nm 3D tri-gate transistor technology, so price will be a key differentiator in this space as well.