With New Horizon and CES behind us, we now have much more information about Zen and Ryzen. However, there still remain many unanswered questions going forward for AMD’s plans. Luckily for us, AMD has shared some more information in the form of an interview with the company’s own Robert Hallock.
According to Hallock, there will be more than one Ryzen CPU available at launch. Since we know that the building block CPU Complex is 4 cores, the quad core units and obviously the 8 core 16 thread variants will be launching for sure.The only possible laggards are the lower clocked octa core and the hexa core units which may have to wait for enough binning to happen. AMD has also confirmed that it will be a hard launch so hopefully supply won’t be an issue. We also get more confirmation that all the Ryzen CPUs will be unlocked and come in at or under 95W TDP.
We also get a bit more detail on Smart Prefetch and Neural Net Prediction. From what has been revealed, it looks like Smart Prefetch is just a rebranded branch predictor but obviously revamped and improved for Zen compared to Excavator. For Neural Net Prediction, it basically learns the type of work being executed and rearranges the workload to best optimize for performance. This seems like an advanced version of out of order execution but more smartness thrown in. Combined, these 2 improvements are apparently a hefty chunk of the 40%+ IPC gain.
Neural Net Prediction should also tie in nicely for SMT as well. With some duplicated hardware, the CPU has more room to play around with rearranging instructions not only for its own thread but for the secondary thread as well. Overall, the various buffer and queue size improvements point to something at the level of Haswell/Broadwell, exactly where AMD appears to be targeting.
Just as Intel has gone wider with Sandy Bridge-Haswell-Skylake, AMD has done the same thing with Zen. Given the lackluster Bulldozer design, these changes will provide an even more dramatic uplift for AMD. If things paly out well, I would not be surprised to see IPC surpass Broadwell in some cases but it remains to be seen.
