Reddit user trander6face published a big roundup of several interesting AMD Zen related rumors that popped up recently. As always, I suggest taking this with a grain of salt as there's no way to judge the accuracy of the rumors.
There's some encouraging stuff in there but also some scary stuff like the news that AMD's Zen is currently suffering from a major bug, similar to the TLB bug that was found in the first Phenom CPUs almost a decade ago. The source claims there's a BIOS workaround but it lowers CPU performance by a massive 30-40 percent. Being this close to launch, it could be that Zen is still nowhere near ready and that it may be delayed once more.
The good news appears to be that when everything is working well, performance is very strong versus Intel, especially in gaming it promises to be neck-to-neck. If it's all true, you may be able to get a 8-core, 16-threaded Intel Core i7 6850K equivalent for a mere $300. The source claims the BIOS/UEFI is built onto the CPU, so only AMD can update it or the CPU microcode, and there still seem to be some issues with this system as clearing the BIOS takes extremely long (30 minutes).
Overclocking will reportedly be limited to the AMD Overdrive tool, with no way to adjust settings via the BIOS. There's also a rumor that high-end boards will not be available when Zen launches because vendors don't want to commit too much right now as everything is still changing at a rapid rate.
Here's the post in full:
There are some errata issues present in the current testing samples, similar in a way to the TLB bug of the Phenom. The workaround right now is done via the BIOS. The workaround however, strips around 30 ~ 40% of the CPU performance.
The CPUs are well behind schedule and every day there's real progress and bug fixing being done. Unlike with INTEL's E0 CPUs which make it to the wild that are almost completely final silicon. AMD's samples will continue to get bug fixes right up until retail spec sampling to partners.
In August Clock speeds were 3.8GHz, right now 4.2GHz overclocking is possible, with LN2 5GHz is doable. Again this will change of course, but it is just the current silicon that is behaving like this.
AM4/ZEN uses an SOC design, that means even CMOS/BIOS configuration is on package (not necessarily on silicon, I can't confirm this) so it is possible to clear the "BIOS" and still have old value applied 30 minutes later. How this will be addressed remains to be seen. Perhaps it won't be the same scenario for final silicon
Operating voltages (nominal) are 1.3v and all the way up to 1.5v should be fine it seems for AIO cooling. Frequency scaling isn't a strong point but again that may have everything to do with the process at this point rather than an inherent design limitation.
Performance is particularly strong at this point vs. INTEL's latest offerings. Single thread performance is matching Haswell-E and of course multi-threading performance as well. Tests that are memory bandwidth dependent may go to the INTEL platform simply as a result of having more memory channels, but I can't confirm that right now and have no info on that. The important thing here is that the 16Thread/8-Core CPU is minimum 5960X performance if not better actually. (Based on Cinebench R15) with the error fix disabled.
Can't speak to how well the IMC is working as current samples are locked to low DRAM frequencies (2133MHz and lower) and of course this has an impact on performance.
As stated in the beginning, every week is progress and AMD is working at an unprecedented rate to get these ready by March.
You're unlikely to see any high end boards for the CPUs prior to launch or at launch, simply because no vendors can commit to too much right now as plenty is changing at a rapid rate.
All overclocking is done via Overdrive, you can't change any performance features at all in the BIOS (on to that next) at all.
BIOS or UEFI is actually built into the CPU, so only AMD can update the "BIOS" or microcode. All overclocking must take place within the Operating system
Right now it takes up to 30 minutes to clear the BIOS. If you remove the CPU and place it on another motherboard, it'll have the same settings applied as on the previous board. So debugging is a nightmare
6850K SKU (May not be final designation) is wait for it.... $300 roughly. That's 8 Cores and 16 Threads
AMD's Hyper Threading is called SMU and it is ************ good. The same efficiency as Intel's HT.
Performance is really good, be it SuperPi, Cinebench, 3DMark etc, it's FPU performance is incredibly good and easily matching that of what Intel offers.
Current performance is staggering even though it is limited to 2133MHz (as mentioned before) and NorthBridge Frequency is limited to 2400MHz
There will be a nigher SKU than the 6850K, but it is a higher bin so it will certainly overclock better than 6850K and that may carry a premium price, but unlikely to be double.
There's plenty of excitement from all board vendors about the platform, so we will see how it all pans out. (Especially with the hot mess that INTEL has in store for us H2 2017, that we can leave to another thread)
For Gaming, the CPU is neck and neck with INTEL, even at low res where CPU bound.