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Dasa

AMD Zen

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while this doesnt bode well for the 6-8 core ryzen game performance due to it being a bit like two quad core cpu joined together there is some latency with cross communication between the first 4 cores and the last 4

it suggests the 4 core 8 thread cpu may not see some of the drops that current ryzen reviews are seeing in some games

Edited by Dasa

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So it's a hardware issue because of the rather large latency between cores pinging between the ccx, which cannot be fixed by any bios or os change. The chaotic nature of data in a game, means a lot more pinging between cores.

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it does seem that way but for programs that only need say 4 threads there is room for software optimization to keep it all together

and although programs that can use 8 cores may not scale as well as they could without that latency results of some games like bf1 suggests that games that can make use of 8 cores 16 threads still do better with them than without

 

i have also seen somebody mention that something i think it may have been the ccx was tied to the memory speed which may be part of the reason increased ram frequency benefit ryzen more than other cpu

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I dont know why the early ryzen board uefi restrict memory speed to 2400, if this is the csse.

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apparently the mb makers only had a few weeks with the bios from amd before launch to tweak it and make adjustments they still need a lot of work

the memory controller on the cpu while efficient with bandwidth seems a little weak at handling more than 2x8g ram so bios optimization will probably only get them so far

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Well, I can be a guinea pig if needed....

 

32632586523_d42a063faa_b.jpg

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So far, from building point of view, it has been rather simple and not a lot of issues. I've heard reports that the X370 Prime had problems but not on my machine thus far. RAM is stuck at 2133MHz despite the 3000MHz stick itself so I'll have to manually change the timings. Windows reinstall was rather smooth and hopefully looking good.

 

But the biggest problem is that I cannot access the BIOS with my G510s and had to use an older Logitech keyboard to get into the BIOS. So that's going to be a pain if I want to overclock. Well, time to find what's the timings for 2400MHz and go from there. And it is running at 3.33GHz at stock voltage ATM. I'll try and get it clock higher later on.

Edited by sora3

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https://www.techpowerup.com/231519/amd-ryzen-5-series-lineup-leaked

6803adc80a48.jpg

low clocks on the 1400\1500x is a shame but with some luck they will still hit 4ghz oc

looks like the 6 core cpu keeps the full 16m l3 cache but the 4 core disables the ccx leaving you with just 8m l3 which may also fix some of the latency related performance issues in games with ryzen

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So some additional notes to go along.

 

RAM is very picky with what chips it uses. It seems that my SkHynix RAM is not able to boot the board at the XMP standards. However, I've borrowed another kit with Samsung B die RAM which IS able to boot at XMP profiles which indicates a problem at memory standards for all manufacturers. With the Hynix, I cannot boot above 2133MHz standard JEDEC timings. With the Samsung, I can boot at the XMP standards at DDR 2998 or 3000 which is the kit specified.

 

Using the stock cooler, I can get the CPU up to about 3.5GHz at 1.25v with no noticeable issues. I'll probably update once I've done my gaming stress testing which is Fallout 4 and console spawning...

 

EDIT: Stock Cooler is holding about 65C at gaming with max speed. Whisper quiet as well too. Intel stock coolers take note from AMD!

Edited by sora3
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https://www.techpowerup.com/231536/amd-ryzen-machine-crashes-to-a-sequence-of-fma3-instructions

 

Looks like we have a real issue here!

 

An AMD Ryzen 7-1800X powered machine was found to be crashing upon execution of a very specific set of FMA3 instructions by Flops version 2, a simple open-source CPU benchmark by Alexander "Mystical" Yee. An important point to note here is that this little known benchmark has been tailored by its developer to be highly specific to the CPU micro-architecture, with separate binaries for each major x64 architecture (eg: Bulldozer, Sandy Bridge, Haswell, Skylake, etc.), and as such the GitHub repository does not have a "Zen" specific binary.

Members of the HWBot forums found that Ryzen powered machines crash on running the Haswell-specific binary, at "Single-Precision - 128-bit FMA3 - Fused Multiply Add." The Haswell-specific binary (along with, we imagine, Skylake), adds support for the FMA3 instruction-set, which Ryzen supports, and which lends some importance to the discovery of this bug. What also makes this important is because a simple application, running at user privileges (i.e. lacking special super-user/admin privileges), has the ability to crash the machine. Such a code could even be executed through virtual machines, and poses a security issue, with implications for AMD's upcoming "Naples" enterprise processor launch.

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Missing the point as those instructions were encoded for Haswell. Most of the time, you'll be coding specifically for certain CPUs, NOT someone else's...

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Illegal, unsupported, legal. Doesn't matter. The point is that there's expected behaviours and if a CPU crashes or is able to be elevated to a privelage level it shouldn't be at then it's a big security hole, and especially for enterprise markets puts a big ding in your reputation.

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Ryzen 3 and 5 are like the ryzen 7 with a ccx between sets of cores

 

Ryzen 3: 2:2

Ryzen 5: 3:3

Ryzen 7: 4:4

 

Hence only 4, 6 and 8 cores CPUs for ryzen

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Illegal, unsupported, legal. Doesn't matter. The point is that there's expected behaviours and if a CPU crashes or is able to be elevated to a privelage level it shouldn't be at then it's a big security hole, and especially for enterprise markets puts a big ding in your reputation.

That's true but not true at the same time. It is true that having a CPU doing something unexpected is not something your company wants to deal with. However, it is not true that ALL enterprise markets will be running the same configuration. Most if not all enterprise will be utilising custom-made software that is tailored to some degree to their work.

 

Anyway, I'll digress and get back to what's happened with the Ryzen. ATM, I've managed to boot the Hynix RAM sticks to 2400MHz but any further = board hang so it does seem like the AGESA isn't liking my RAM. BIOS updates is rather pathetic but given how Asus is prioritising the C6H, this does mean that the Prime does get some loving soon. Managed to O/C to 3.7GHz at 1.20v which is rather surprising and I probably can push further to 3.9GHz. Cooling might be a problem but it seems the stock cooler is still hanging in there. I did a burn test with XCOM2 which heats my system hard and the temps were hovering at 62C max. Not bad...

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I'm hearing Ryzen isn't compatible with a lot of RAM. Hope it's just buggy board BIOSes.

Edited by Jeruselem

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I'm hearing Ryzen isn't compatible with a lot of RAM. Hope it's just buggy board BIOSes.

Most of the RAM can boot at standard JEDEC 2133MHz speed and timings. But it is the higher speed that is the problem since the InfinityFabric is dependent on RAM speed. Once the AGESA is settled, then we should start to see a lot more speed into these things.

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It's not like they're done from scratch. The overall framework is much the same, just specifics like register locations that change.

But really, like any new architecture the edgy stuff is where the learning curve is. Look back at most high profile overclocking motherboards, it took some of them multiple months and several Bios revisions before they got near their peak capability.

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