Underclock my cpu

7LoveLess · June 17, 2021

Hello there. I've been searching the internet again and when i search youtube how to underclock your cpu i get 1 hour videos and all overclock. I got two desktops and one of them i want to run as a server and need it to run as cool as possible.

I set the clock speed to 3200mhz but the cpu speed still shows at 4ghz. it's annoying as hell. i don't want this thing to run fast i've change all settings possible. '

I have an asus motherboard B550. I need my base speed to be my cpu speed.

motherboard crashes when i go below 3200mhz

mr cheese · June 17, 2021

Check your actual clock speeds in Ryzen Master. Windows may be reporting it wrong.

NelizMastr · June 17, 2021

Have you also set PBO and similar boosting settings to disabled in your UEFI?

cuvtixo · June 18, 2021

I'm a little concerned about why you want to underclock, and whether you really understand what it is and does. Firstly, search for terms in quotation marks. "Underclock", "Underclock CPU", "downclock" and similar. Also "undervolt", because if you truly can benefit from underclocking, you would likely also want to lower voltage, too. Right away on Youtube I found "I Underclocked My Ryzen 5 3600 To 800MHz..." https://www.youtube.com/watch?v=dU0--0gyxksop

Quote

I need my base speed to be my cpu speed.

I have no idea why you would want or need that.

Bear in mind that in laptops, the CPU is already underclocking itself automatically whenever it's not plugged in. If you are still determined: after you've made adjustments in the UEFI (BIOS), run a stress test for about an hour. Prime95, PassMark, and Intel Processor Diagnostic Tools are all good, and maybe more importantly, better than Windows Task Manager. You want to check out the heat generated according to this test. The CPU running cooler is a good indicator, better than a Task Manager report, to check if you've achieved underclock.

I'm not sure your experience with overclocking, if you've done it, you may know that CPU speed is determined by the following formula: Front Side Bus speed (FSB) x Multiplier = CPU Speed. FSB is also called "Memory BUS" or "System BUS". In underclocking, you want to divide reported CPU speed by this speed. When overclocking, you can get incremental speed boosts that don't quite match a multiplier of FSB, but in underclocking, you're not going to get uneven multiple, CPU speed has to divide evenly by the FSB. You report "motherboard crashes when i go below 3200mhz" Are you sure that's a set limit and not just because you are attempting uneven multiples of the FSB?

My experience, probably like most gamer's, with slowing a CPU is from trying to run old 80's DOS games on 90's Pentium and later CPUs. In more recent machines, it's a matter for software emulators like DosBox, not something you'd try to achieve in hardware. Maybe you haven't adjusted Power Management off of "Performance" and on "Balanced"? I would assume you'd have done that already, but maybe I shouldn't make that assumption. Is this about getting the CPU to run cooler? Lower power consumption? I just don't get what you are trying to achieve here, it doesn't make much sense to me.

7LoveLess · June 18, 2021

i did it but forgot what it was called that made it stay at lower speeds and i'm super happy. CPU is always cool even when running at high loads. I underclock the ram too from 3200 stock to 2400 lower the cpu core volts to 1.1 here is a pic. once i can restart the pc which will be a while i will lower the speed even more because what i need doesn't need high clock speed. i'm using 3900xt for my rig but when i saw the 2700x for $130 at microcenter wow i got it and i couldn't be happier.

What i change was something that has a 100 number to 95 or 90 somewhere along those numbers and the speed stayed low.

Thanks for those who reply.