Leaked Bulldozer benchmarks may give glimpse of AMD's future

AMD logoWith so much riding on AMD's upcoming server architecture, codenamed Bulldozer, it's no surprise that the recent appearance of a set of benchmarks of a Bulldozer engineering sample is creating quite a stir. Interpreting these benchmarks is not easy, given their complete lack of critical context (i.e., compiler options, software versions, optimizations, etc.) and the unknown state of the sample chip that they were run on. But David Kanter at RealWorldTech has done a heroic job of taking them apart and looking for clues as to what, if anything, the benchmarks signify.

I won't recap his analysis here, since it's perfectly accessible and worth reading. But I will summarize a bit.

First, as was noted above, the benchmarks are so devoid of critical contextual details that they're borderline worthless. Optimizations can make huge differences in performance, but it's impossible to tell what, if any, optimizations were applied in this instance. It's also the case that the engineering sample itself seems to be crippled in a few respects. The clockspeed is an unnaturally low 1.8GHz, and the part's extremely poor memory performance suggests that the probe filter was disabled and that valuable bandwidth is being eaten up by cache coherence traffic.

All of that said, Kanter tries to isolate out a few benchmarks that might provide some glimpse of how Bulldozer's will ultimately perform vs. its predecessor, Istanbul. The results are a mixed bag.

Bulldozer's "cores"—AMD calls them "modules" since, due to 'Dozer's unique design, each module is equivalent to some one and a half normal cores—range from 0.6 times the performance of Istanbul's cores to 1.3 times. This is a huge amount of variation, and it appears highly workload dependent.

When I saw these results, I was immediately reminded of the first benchmarks that came out for the hyperthreaded Pentium 4. Hyperthreading (or simultaneous multithreading as it's commonly called in non-Intel implementations) turned out to be a mixed bag for the P4, sometimes reducing the per-core performance, and sometimes boosting it. And in fact, this sort of 0.5x to 1.5x range was about what we saw at hyperthreading's debut (if memory serves).

I've previously described Bulldozer as a sort of "extreme hyperthreading" approach, where the integer ALUs are replicated along with the normal replication and expansion of queues and buffers. So intuitively, it makes some sense that Bulldozer will give SMT-like results. Or, to put it differently, SMT is sort of finicky and your mileage will vary depending on the workload; it may turn out that Bulldozer is also finicky, and that it's going to work great for some niches and not-so-great for others.

Right now, however, all of this discussion is extremely preliminary—probably even premature. As Kanter points out, there are too many unknowns with both the engineering sample and the actual benches to lean too heavily on any interpretation. But I will admit that these results have got me thinking, and my expectation now is that Bulldozer will benefit very heavily from optimization work, and that it will be more finicky than Istanbul about what workloads it likes.

Source: Ars Technica

Tags: AMD, Bulldozer, CPUs

Comments
Add comment

Your name:
Sign in with:
or
Your comment:


Enter code:

E-mail (not required)
E-mail will not be disclosed to the third party


Last news

 
 
Highlights of the new feature update include a tweaked interface with Fluent Design elements
 
It’s now open to third-party developers and designed for smart home devices
 
Prices start at $1499 for the 13.5-inch model and $2499 for the 15-inch model
 
Users claim the Start menu isn’t working after the upgrade
 
It will release its first all-purpose AI chips by the end of 2017
 
Android 8.1 Oreo arriving on Pixel phones "in the coming weeks"
 
The Snapdragon 636 also comes with support for modern ultra-wide FHD+ displays
The Samsung Galaxy A5 (2017) Review
The evolution of the successful smartphone, now with a waterproof body and USB Type-C
February 7, 2017 /
Samsung Galaxy TabPro S - a tablet with the Windows-keyboard
The first Windows-tablet with the 12-inch display Super AMOLED
June 7, 2016 /
Keyboards for iOS
Ten iOS keyboards review
July 18, 2015 /
Samsung E1200 Mobile Phone Review
A cheap phone with a good screen
March 8, 2015 / 4
Creative Sound Blaster Z sound card review
Good sound for those who are not satisfied with the onboard solution
September 25, 2014 / 2
Samsung Galaxy Gear: Smartwatch at High Price
The first smartwatch from Samsung - almost a smartphone with a small body
December 19, 2013 /
 
 

News Archive

 
 
SuMoTuWeThFrSa
1234567
891011121314
15161718192021
22232425262728
293031    




Poll

Do you use microSD card with your phone?
or leave your own version in comments (4)