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For reference, this is the machine I have:
Ryzen 9 5900HS CE with 4266 Mhz LPDDR4x. And it runs the Infinity Fabric (FCLK) at a measly 1600Mhz, while it should be 2133Mhz.There's absolutely no reason it shouldn't be possible to change it, either through a lightweight Ryzen Master app for mobile APU's, or start pressuring OEM's to include it in their BIOS.
There is AATU (AMD APU Tuning Utility), but this does not allow changing FCLK, only control the dynamic FCLK scaling.
This is not just a problem on the specific laptop I have, this is a widespread issue that needs addressing. It's literally performance we are missing out on...
EDIT: Should be possible for ALL Ryzen APU's.
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Well, on Ryzen 5K APUs, IF speed doesn't matter as much as on Ryzen 4k APUs.
TL;DR: IF clocks only matter for communication between CCXs. The Ring Bus in the Zen3 CCX runs on a completely different clock domain that is not exposed by any public API.
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Given what we know so far about FCLK speeds it's unlikely you'd be stable at 2133. Definitely sucks that you can't change it though
ID: hd3zv4cID: hd40394And that's Renoir (Zen 2)...
ID: hd40crfWe should have the option as a consumer to change this regardless of the crap BIOS OEM's make. Stability is another matter entirely. But I don't think Cezanne has any issues running at such high fclk...
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Have you seen if you have the last bios for your laptop? I had this issue on mine that ram was running lower than the specs, updating bios fixed it.
ID: hd45f92Unrelated. RAM is running at advertised speeds, but FCLK (Infinity Fabric) should be 1:1 ratio of DRAM for optimal performance thus 2133Mhz and not 1600Mhz.
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What software have you used to find out the Infinity Fabric (FCLK) ?
ID: hd4fgspHWINFO64
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Read AMDs Bios and Kernel Developer guide so you can change the clocks peed yourself.
ID: hd4fht7Do you have a link?
ID: hd4jp3vIt's a joke.
AMD doesn't give that info out anymore.
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There is another side effect of this: The memory controller must run in 2:1 mode because UCLK must be <= FCLK.
So not only do you get the latency penalty from async FCLK:MCLK, but you also get the latency penalty from 2:1 mode.
I hate OEM crap.
ID: hd4kem2Exactly. The dev from AATU doesn't think FCLK above 1600 will ever happen on mobile APU's though...
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They never will because of power consumption. Memory clock is already dynamic in mobile chips, both Intel and AMD, and I suspect FCLK is also dynamic as well, because of the same reasons.
ID: hd4mtc4If it is dynamic there's no reason to limit it's maximum. Surely there's room to optimize the algorithm so it doesn't cause excessive power consumption while not on AC or something.
At some point it will happen, but probably not with this generation
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Yeah this is ridiculous, they should really stop blocking memory tuning (lack of XMP hurts especially) and Ryzen master. State of laptop memory is just sad.
ID: hd4n6u8Couldn't agree more
引用元:https://www.reddit.com/r/Amd/comments/ppevq7/amd_please_let_us_adjust_infinity_fabric_speed_on/
Not sure about that. Desktop has memory overclocking has been impressive.