SPI flash / SMI/SMM + some observations (AM5)

[Sandy]

The USB port roulette problem is getting increasingly sophisticated! It was concluded a long time ago that the issue stems from the USB ports. Some motherboards have one or two usable low-latency ports, while most motherboards have all of them malfunctioning. Try buying a PCIe USB card with an NEC chip; if that doesn't work, return it. Currently, this is the only solution.

i removed my xhci reneasas card due to no effect but keeping my intel nic card due to lower cpu overhead. did you tried the spi bus speed trick?

I don't even know what an SPI bus is... I just used a very simple method to test the USB port latency. I removed the keyboard and only kept the mouse, and repeatedly moved the mouse in the CS 1.6 game to observe the difference in input latency. Finally, I successfully found my "golden port"—the second blue port. No matter what I tested, I couldn't make this port malfunction. I'll observe it for a while longer. If it's finally confirmed that the latency is caused by the USB port, I'll come back and report~

[Muji]

agN, why do you think its something related to spi. I've been watching your videos and you have tested on a different intel cpu setup and amd cpu setup. why are you so certain its something related to that? why cant it be your gpu or power supply? I have a similar psu. a corshair rm750x and my gpu is an oc manufactured similar to yours. you've tested with two different motherboards which makes it highly unlikely the issue is related to the motherboard.

[agendarsky]

if any driver , firmware level or os level depends on information on device that use bus , and is polled and slow frequency then i think it can lead to decreased responsiveness of system, either voltage or clock adjustments. Also , if this transaction is being handled as system management interrupt, there you have your answer for why we cant track this issue by latency/benchmarking tool, because os is not aware of that and thoose microseconds spend in smm is literally wasted cpu cycles that could be used to execute code.
Psu is not issue for sure, im kinda tired of repeating it every single post but i find very important to keep that in mind, unlike many new users posting mostly unrelated stuff, or things that has been tested like 5 years ago and except hyote or slender i can't see "old" users being active so cycle of placebo will repeat. To clarify what i have been talking about when i told i keep repeating this is i know exact same moment when this issue started for me back in 2011 while i was still playing cs 1.6 , basically i have grown on fps games like quake or whole goldsource engine games like cs , hl, tfc, or even tf2 and had identitcal setup from 2007 to 2011 until change has been made. During that era , it was golden times, every thing ran buttery smooth and responsive even if some fps drops occured. Actually this fps drops sometimes drove me mad during random pcw matches so i've tried to overclock my cpu and bricked my motherboard, at that time it was already old platform but i was broke teenage and my dad althrough he has been tech enthusiast he did not have money to buy me whole new platform from scratch, but got me new motherboard but it already needed new rams and new gpu (ddr400 to ddr2 and agp to pci-e switch) , psu, disks, CPU and even os (win xp service pack 3 ) remained same and well the first match i've played i instantly noticed there was something off, i knew has vsync lag is percieved , it's more like delayed mouse movement but still u can do perfectly crisp turns , your bullet spread is little bit slower because obviously you are having 75 fps instead of 101 at that time but despite that u just disable vsync, maybe set your pre-rendered frames to 1 and u didnt need to touch anything really, but it was different , too many things affected at once, the most noticable that drove me crazy is not even the input latency itself but how slow and "heavy" your characters feels, especially when you try to strafe there was literally time that my finger needed to spend on keyboard to move instead of action being instant, and even when you finally get your character to move it felt out of time, i even think that it take more time to stop, i watched my old demos i was collecting from matches when there was no problem and i could see a lot more agressive movement and less time i needed to strafe burst strafe burst shoot, i tried to imitate it on local lan server and it was obvious that time signature of whole system is off, i couldn't replicate that movement because my brain couldn't adjust to it, if i tried hard it looked like random strafe and random shoots and that's the most obvious sign of that you have this problem instead of random input lag caused by bad driver or mouse sensor it was obvious from first plays that this is something more serious. If system generates too much SMI event's it stalls your cpu for microseconds and also it stops tsc from counting when in smm mode. The rest of the story is like i went on my life , gaming was always my most loved loner hobby , i continued in school , i got a job and eventually in free time i was reading articles, i was trying different regedit stuff, whatever ,just trying to take a wider image. Then from money i earned i bought completly new amd platform, same there , and since then i have been on like 7 or 8 platforms both amd and intel, different motherboard brand always high or mid-high category, different ram kits, deticated sound cards, usb cards, network cards, with slight or no improvement, in 2013 i just stopped playing cs and started playing dota with friends from high school, still ocassionaly messing with os parameters, 5 years ago i was kinda into emi theory but back in my head i was sceptical because from 2006 to 2011 i wasnt event aware that something that serious even exists, and suddenly when i change the motherboard and other stuff i'm supposed to believe that some random electrical event occurs in my area affecting my devices? even when i moved to different location ? on every platform? why do people report (including me) that some random voltage value makes things noticable better or worse, why locking every value at fixed value , not using single auto value doesn't make any difference? It's like i want to dismantle whole system on parts , part by part , rams, imc, gpu, bus which gpu sits on, bits u can toggle and and can be found on platform specific documentations published by amd or intel directly, thoose are very specific and are not exposed in bios , not even in hidden part. I'm not even mad about this problem anymore even when i spend so much money on it, it's driven by both, curiosity and madness because paying for high end hardware and we're having terrible performance while we blaming game devs. So.... there you got your answer why i think it's motherboard problem, or to be specific motherboard firmware problem and if the architecture is not the issue you've gotta look on other stuff on motherboard which in this case is sensors, embeded controllers and acpi firmware and i'm more like embracing to focus on how power / thermal telemtry works than focusing on actual voltage settings. Altrough there can be some issue or more like mechanism implemented on gpu firmware that causes this ( actually lot of stuff dynamic power saving stuff https://screenshot.cz/BYTLB/ ) it still doesn't explain why this happens on iGPU also. And psu? Yeah, i've already had many psu's.

Despite spi bus and smi theory, this things can be suspect too. but before some soc engineer dont take this seriously and start investigating we will never have answer. This is way too low-level .

PCI-E: chipset routing and switch arbitration: depends purely on motherboard, according to avaiable informations single switch can adds up to 60 to 300 ns latency in one transaction= request + process + response. Keep in mind that msi interrupts are pci-e based transactions too and on modern motherboards it doesn't matter if you turn msi off , modern motherboard don't have physical irq pins so they are emulated as legacy interrupts but still handled by pci-e.
PCIE-E: high completion timeouts + transaction reoders.
RAM/IMC: Command reordering, wrong ram training or wrong on-die termination causing jittery data eye, on-die termination was introducted in DDR2, DDR400 systems were using physical termination resistors on board.

The complexity of this problem is ridiculous, for me personally i completly switched from " i want most of the stuff handled by bios/firmware" to " i want most of the stuff handled by OS"
Sorry for bad grammar, too tired to double check this post

[agendarsky]

main post edited to make it more clear

Found my nvram from Intel Z90, default smm values should be good as it is but still gonna post them. Unfortunately can't find anything about memory private regions

Setup Question = SMM MSR Save State Enable
Help String = Enable/Disable support for MSR Save State
Token =2B5 // Do NOT change this line
Offset =22A
Width =01
BIOS Default =[00]Disabled
Options =*[00]Disabled // Move "*" to the desired Option
[01]Enabled

Setup Question = SMM Use Delay Indication
Help String = Enable/Disable usage of SMM_DELAYED MSR for MP sync in SMI
Token =2B6 // Do NOT change this line
Offset =22B
Width =01
BIOS Default =[01]Enabled
Options =[00]Disabled // Move "*" to the desired Option
*[01]Enabled

Setup Question = SMM Use Block Indication
Help String = Enable/Disable usage of SMM_BLOCKED MSR for MP sync in SMI
Token =2B7 // Do NOT change this line
Offset =22C
Width =01
BIOS Default =[01]Enabled
Options =[00]Disabled // Move "*" to the desired Option
*[01]Enabled

Setup Question = SMM Use SMM en-US Indication
Help String = Enable/Disable usage of SMM_ENABLE MSR for MP sync in SMI
Token =2B8 // Do NOT change this line
Offset =22D
Width =01
BIOS Default =[01]Enabled
Options =[00]Disabled // Move "*" to the desired Option
*[01]Enabled

Setup Question = EC PECI Mode
Help String = Switch eSPI PECI Mode or Legacy PECI mode
Token =2861 // Do NOT change this line
Offset =55
Width =01
BIOS Default =[00]Legacy PECI mode
Options =*[00]Legacy PECI mode // Move "*" to the desired Option
[01]PECI over eSPI mode <--- use this

Setup Question = Flags
Help String = HID Over SPI Flags
Token =11DE // Do NOT change this line
Offset =7B5
Width =04
BIOS Default =[00]Single SPI Mode <--- try QUAD
Options =*[00]Single SPI Mode // Move "*" to the desired Option
[4000]Dual SPI Mode
[8000]Quad SPI Mode


Setup Question = Connection Speed
Help String = HID Over SPI Connection Speed in Hz
Token =11ED // Do NOT change this line
Offset =7C1
Width =04
BIOS Default =<17000000>
Value =<17000000> <- try 50000000 or different value ,

[ablemor]

An external PCIe USB card does nothing I even tried one powered by DC, where the computer only received the data signal, but it still felt "floaty." ITS emi rfi

[ablemor]

By the way, a certain type of power supply can help, but even that only reduces the lag by about 20–30%.

[Yagami]

If the issue is above the kernel, does that mean it affects most modern computers?

Like I mentioned on reddit, I suspect the issue might be related to RAM timings or even the memory controller.

I bought a new RAM kit that's on my motherboard's QVL. Running it at JEDEC speeds, with no other BIOS changes, my mouse precision improved dramatically. However, the sluggish feeling is still there in multiplayer FPS games. It feels like I'm playing at 60 FPS—as if my character weighs 200 kg—even though the game is actually running at 500–700 FPS.

I'll definitely give your findings a try. Thanks for sharing!

[agendarsky]

If the issue is above the kernel, does that mean it affects most modern computers?

Like I mentioned on reddit, I suspect the issue might be related to RAM timings or even the memory controller.

I bought a new RAM kit that's on my motherboard's QVL. Running it at JEDEC speeds, with no other BIOS changes, my mouse precision improved dramatically. However, the sluggish feeling is still there in multiplayer FPS games. It feels like I'm playing at 60 FPS—as if my character weighs 200 kg—even though the game is actually running at 500–700 FPS.

I'll definitely give your findings a try. Thanks for sharing!

Yea bro , that heavy feeling literally hurts brain when trying to adjust to that sluggish game tempo and yeah i think it's firmware level issue that exists on every modern motherboard but it's strenght depends on vendor individual implementation , from software side , great examples are ACPI tables. that are literally board and bios version specific. Btw, i just realized that i've been wrong about smi events and pausing tsc counter , atleast not on modern pc's since its invariant counter but maybe that desync can came from when various cpu's enter smm in different time. As for the ram speeds, by the logic of whole this process ram stabillity must affect it because smram is private reserved region in your actual memory, i don't want to blindly support my theories but it just makes sense, currently i'm running my 7200mhz kit downclocked to 6000 cl36 to make it behave like regular gaming kit with average timings, i will try to oc back to 6000 cl 28 tommorow or in friday to see it's effect. By the way today i've reinstalled both Linux and Windows, i've swap their location because i want 2tb to be for Windows and 1 tb for CachyOs, and i've installed chipset drivers offered by adrenalin software when instaling gpu drivers, i went to play some csdm and it's state was something unusual, game tempo was fine, input x and y axis was fine, smooth and no jittery, but there was little bit of click latency , not 100 % perfect but compared to what i'm used to , i would rate it at 90 percent which is not enough for me, surpsingly downloading x870e chipset drivers from amd site and after restart its 100 % again. As for now, i'm doing opposite in my bios settings, as much stuff it's possible must be controlled by os , not firmware.

ablemor: oh yeah and what is that? multirail psu? server psu?, this was tested 5 years ago and i yeah i also ditched away my xhci card that also is powered from psu from my computer. here is some interesting reading for you
https://edc.intel.com/content/www/id/id ... tion/1000/
https://web.cecs.pdx.edu/~karavan/resea ... eprint.pdf
https://uefi.org/sites/default/files/re ... notice.pdf

[ablemor]

No... I think the Y-capacitors in the power supply are playing a part in this too. It would be best to have as few of them as possible the problem is that there's measurable voltage on the case. Anyway, try a power supply that uses a Double Forward topology instead of LLC or whatever else, look into it. The emitted frequency actually matters this is 1000% EMI/RFI, not a BIOS setting issue. You guys always post something here, but there's never any real result, and there are already 10,000 threads about it.

When I use a Double Forward PSU, the mouse feel improves immediately it's less floaty, and I hit my shots correctly more often.

[ablemor]

It could be that my computer's power supply is infecting itself the noise generated by the SMPS simply can't escape my PC, it passes through to the monitor, then comes back through the DisplayPort cable. I know this is where the problem lies. Also, anyone messing with the Windows Registry is completely lost in my opinion this issue persists on Linux too, I've tried it. But the bottom line is even if you buy an expensive power supply, it won't help, and neither will some garbage UPS.

Plus AGN guy, didn't you solve the issue with USB 2.0 controller mode? Why are you on the AM5 platform, and didn't you retire a while ago?