The most I think about it the more I can't help but feeling like "Zen" won't be all it's cracked up to be.
Consider, AMD is claiming that Zen will offer 40% higher IPC than Excavator. Fine, the only desktop Excavator is the Athlon X845, a dual module quad core part. The bulldozer family of cpu's count "cores" as 1 ALU coupled with half of the 2x128bit FPU/SIMD unit, so that each fully pipelined "core" can handle on complete instruction string. It's also clocked at 3.9ghz with 4.1ghz turbo.
Zen is expected to be a more conventional design along the lines of pre-Bulldozer AMD cpu's and Intel's offerings, meaning multiple ALU's per core, each core has it's own L1 and each core has it's own SIMD/FPU.
Zen will also feature AMD's version of hyper-threading. HT in Intel cpu's, in multi-threaded non-HPC workloads add about 25% performance increase, assuming a similar speed up in AMD's Zen cpu's and assuming that all Zen's will feature SMT (as AMD has indicated), it would seem that much of that 40% IPC improvement comes simply from a design that implements SMT.
Now if Zen's are clocked lower than Excavator that would offset the other 15% improvement, not to mention that since Zen is supposed to use DDR4, 5% of the speed up comes from that, so I wouldn't be surprised to see the first AMD quad core 8 thread Zen cpu's barely outperform the current crop of FX cpu's on desktop applications.
It seems to me that AMD is targeting the very lucrative HPC market once again with Zen, just as they did with Bulldozer. The proof is in the Linux kernel patch which makes reference to a 32 core 64 thread Zen based cpu, such a cpu is obviously meant for massively parallel workloads such as those found in HPC applications. The problem is that what is good for HPC workloads is not necessarily what's good for desktop applications.
I think for enthusiasts the real must have cpu will be the rumored 5ghz quad core Xeon cpu Intel is said to be planning. The other interesting part will probably be the new AMD APU's, which AMD has said will be capable of graphics at least as good as the PS4 and XBox One.
That APU would be great for budget gamers and if adopted widely could become the new baseline that game developers target, meaning we could see much nicer looking games across the board as a result of that cpu.
But the non-APU Zens? I have this sinking feeling that they won't be anywhere near what most of us are hoping for and Intel probably knows it as well which is why the upcoming Kaby Lake are all going to be quad core offerings similar to Skylake, unlike the the previously rumored 6 core main stream offerings that Intel had been considering.
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Why do I get the feeling that Zen will be a disappointment?
Last edited by jagabo; 12th Feb 2016 at 11:03.