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*** AMD "Zen" thread (inc AM4/APU discussion) ***

Bear in mind (up to) 2 GiB of your RAM will be dedicated to the IGP, so with 8 GiB you only get 6 GiB system RAM. Wasn't enough for me with games like Cities Skylines but for most games is probably OK.
 
WTF,is happening here:

https://www.pcgamesn.com/amd-raven-ridge-overclocking

A weird bug feature has appeared during our testing of the Ryzen 5 2400G Raven Ridge APU that means our chip overclocks a by huge amount when you put it to sleep. You may have seen some leaked benchmarks appear online, and yes... they're true, it can hit 4.56GHz on air.

Check out the full review of the AMD Ryzen 5 2400G.

This bug feature is either in the darling little MSI B350I Pro AC motherboard that came as part of the Raven Ridge test kit, or the Ryzen 5 2400G APU itself. It sees one of them automatically overclocking the chip far beyond what I’ve been able to do in the BIOS, or with the Ryzen Master utility.

In my testing I’ve only been able to push the top Raven Ridge APU up to 4.05GHz using simple multiplier tweaking. I have been able to get the chip booting into Windows, and running some light gaming workloads, at 4.2GHz, but putting any serious CPU load onto it the chip falls over.

But, with the bizarre sleepy overclock, that same APU is able to top 4.56GHz and remain completely stable under full gaming and CPU testing loads.

AMD Raven Ridge overclocking

I discovered it completely by accident while testing the stability of my earlier overclock. I left the test bench to do something probably super-important, and when I came back it had put itself to sleep. On waking it up I noticed CPU-Z was reporting a much higher clockspeed because of the new BCLK setting.

Normally the 2400G runs at a base 100MHz with the multiplier helping to then create the 3.6GHz and 3.9GHz stock clockspeeds of the chip. Where it gets really weird is that neither the Ryzen Master utility, nor the MSI motherboard BIOS, allow you to tweak the BCLK.

Initially I assumed it was a mistake. Pre-release platforms often display weird results in monitoring apps - part of the fun of putting together launch day reviews - so I figured there was nothing to it. But after testing and retesting it became obvious the overclock had stuck and this mighty chip was overclocking like a hero.

It's potentially down to the C-state settings in the BIOS I've disabled due to some issues I had getting 3DMark to run on the AMD test platform at the beginning. It's also quite possible it's the old Ryzen sleep timer bug appearing again.
Click to expand...

But it’s completely repeatable. Every time I reboot and drop it into sleepy time mode for a heartbeat the BCLK setting pushes itself up to a heady 112.50MHz. With the x40.5 multiplier I had in place that meant it was sitting pretty at 4.56GHz when it woke up.

At that speed the performance numbers are incredible. The 2400G hits around 1,000 and 187 for Cinebench's multi and single-threaded tests, making the $100 more expensive Intel Core i5 8600K look a little foolish. And, with a healthy 1.5GHz clockspeed on the Vega 11 GPU, the gaming performance gets mighty playable at the top 1080p game settings. You do need some speedy, pricey DDR4 memory to get the most out of the graphics cores - this Vega chip has no HBM2 to call its own - so that does affect the overall platform costs.

But it's also possible to use the overclock with a discrete GPU in place too. That gives it a heroic level of graphics support from such a budget slice of silicon.

Unfortunately I haven't been able to replicate the overclock in any other motherboard. The only one we have that allows manual overclocking of the BCLK is the Asus Crosshair VI Hero, and the pre-release BIOS update doesn't seem to allow any sort of overclocking on our Ryzen 5 2400G sample.

Now, the likelihood is that the sleepy overclock will get patched out of the platform, but please, AMD, give us the tools to tweak the BCLK ourselves across the board, it potentially makes a massive difference to the chip’s performance.
Click to expand...

So,potentially with BCLK overclocking you could get decent overclocks,but it seems BCLK is locked down.
 
CAT-THE-FIFTH said:
WTF,is happening here:

https://www.pcgamesn.com/amd-raven-ridge-overclocking


So,potentially with BCLK overclocking you could get decent overclocks,but it seems BCLK is locked down.
Click to expand...
Almost certain this bug existed with Ryzen when it was first released also, it was just a timing bug making applications think tasks had been completed faster than they had and reporting clock speeds higher than they were. Probably the same here since we know the chips cannot get anywhere near 4.5 GHz without mental voltage.

So many people are going to read that crap and get completely the wrong idea. The fact that the person who wrote the article apparently doesn't even know Ryzen had a similar bug is pretty bad. Hopefully they retract it soon before this nonsense spreads. :mad:

CAT-THE-FIFTH said:
Hardware Unboxed overclocked the GPU to 1.6GHZ using the stock cooler!!
Click to expand...

Yeah but it supposedly makes not much difference in performance. Even the difference between Vega 8 and Vega 11 at stock is 10% or less, according to Stilt I think. Basically they are bandwidth limited rather than clock limited.
 
DragonQ said:
Almost certain this bug existed with Ryzen when it was first released also, it was just a timing bug making applications think tasks had been completed faster than they had and reporting clock speed higher than it was. Probably the same here since we know the chips cannot get anywhere near 4.5 GHz without mental voltage.
Click to expand...

I dunno,but it would be useful to see if BLCK overclocking would work better with these newer chips.

DragonQ said:
Yeah but it supposedly makes not much difference in performance. Even the difference between Vega 8 and Vega 11 at stock is 10% or less, according to Stilt I think. Basically they are bandwidth limited rather than clock limited.
Click to expand...

It does with the Ryzen 3 2200G,but I collated lots of reviews so you can check:

https://forums.overclockers.co.uk/threads/ocuk-ryzen-apu-review-thread.18811382/

This one shows the effect on the Ryzen 3 2200G:

https://www.techspot.com/review/1574-amd-ryzen-5-2400g-and-ryzen-3-2200g/page6.html
 
From that Stilt review: "Similar to Zeppelin, the frequency headroom for the CPU cores themselves is very slim over the stock frequencies. The typical, highest practical CPU frequency will be around 3.85 - 3.95GHz depending on the silicon quality."

Hmm...

Also.. TIM?!?! Didn't they learn about about this crap when Intel started using TIM instead of solder :( bah.
 
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