Monday, October 29, 2012

AMD Vishera launches,finally. Bulldozer done right

1 year has passed since my last post which covered ,you guessed it,a Piledriver core. I predicted 4.2Ghz base clock (overstated by 5%) and 5% higher IPC( understated by 3% on average,it varies between 5% and 20% depending on workload). So basically I predicted 4.2Ghz Vishera and expected 20% higher performance. What we get is 4Ghz Vishera that is ~15% faster,pretty much what I said minus the higher clock ;). Also Vishera, as we will see later, outperforms Bulldozer core on the same clock in games by a very high 13.5%,a feat I didn't expect! On to the Piledriver launch details then. But first a little bit of history.

AMD promised a lot of things when it comes to long awaited Bulldozer core. On many levels they didn't deliver but on some they did. Now,one year after Bulldozer version1 ,we finally have a "quick  fixed" Enhanced Bulldozer(how AMD called it 1 year ago). Does it deliver? Yes it does. On many important levels,this core is what Bulldozer should have been when it launched. But AMD needed something last year and they went with what they have. Now finally,albeit late, the Piledriver delivers. It's faster per clock,consumes less power at the same targeted clock and does this without Resonant Clock Mesh or a smaller node. It's a tick+ in intel's terminology since what it delivers in IPC and clocking is more than what IvyBridge did with a uarchitectural tweaks and a die shrink.

Some relevant links to reviews(there are many reviews, for a complete list go to this topic @ XS where Flanker did a great summary of all the data):,3328.html

Models summary:

Piledriver die shot:

Here are slides that detail uarchitectural improvements:

And how does it do in reality versus Bulldozer version1 you ask? Look for yourself: chart

7.7% average IPC gain in application workloads and 13.5% average IPC gain in gaming workloads. Job well done AMD! This core does work more efficiently AND clocks higher within same power envelope which results in greater power efficiency.

For comparison between 3770K,Thuban,Bulldozer and Piledriver (all @ 3.6Ghz) check planet3dnow review linked above. Piledriver comes really close to 3770K in many real life  workloads and offers great bang for the buck.

Average performance in applications:
FX8350 @ stock offers 94.4% of 3770K stock performance for 100$ less. The above is average from many workloads some of which are not multithreaded. A 15% improvement versus 8150 is very good result and is close to what I speculated 1 year ago.  FX8150 has very high full core/half core turbo of 3.9Ghz and this is why the difference is not more than 20%. If it ran closer to 3.6Ghz in most workloads(as it doesn't,it's at 3.9Ghz most of the time), the difference between 8350 and 8150 would be >20%.

Gaming performance average:

 FX8350 is considerably slower (at stock) than intel parts in selected gaming benchmark suite used(very CPU bound games and Skyrim is one that particularly doesn't like AMD CPUs for some reason so the average is dragged down quite a bit). Still FX8350 does very nicely compared to all other AMD CPUs and now has a respectable score ,basically on par with 3240 i3 and some 15% lower than Quad core Ivy Bridge 3330. This is more than enough level of performance for modern games and unless one plays exclusively those few titles that run bad on AMD hardware(like SC2 or Skyrim), FX8350 will be a great budget gaming processor. Once OCed to ~4.6Ghz which is common for 8350/8320, this chip would be ~18% slower than what 3770K offers in games used,for 100$ less.

In summary of this short post, FX8350 is what AMD promised: a better Bulldozer in every way you can think of. It has considerably higher IPC ( for a tick or a "quick fix"), it clocks higher and does it within same power budget on the same (bad) 32nm GloFo process node. Let's hope AMD brings SR core to FX line and doesn't abandon this market segment like some rumors are suggesting. Even with Haswell on the 2013 horizon I believe Steamroller has a chance of coming ever closer to intel desktop lineup since it massively improves single thread execution ,an area in which AMD still lags intel by a quite a margin. Multithread performance is good now and is very competitive. The last "bad" thing about BD/PD is power draw and this won't be fixed until 28nm node is ready. For those who don't mind about higher power draw (most don't since PC idles 95% the time anyway and difference is zero there), the FX8xxx line is the perfect choice for a mainstream PC desktop user on a budget.