AMD 5800X3D, the new King for flight simulators?

[edmuss]

I run mine with a 25mv undervolt in all cores via PBO 2 tuner and it sits at 75°C on a cinebenchR23 run, all cores pegged to 4.45ghz which is the most it gets to. I tried -30 but it gets unstable, as it is the core voltage never goes much above 1.2v and the normal max is 1.35v I think.

In DCS it sits between 55°C and 70°C with the average at about 62°C

[coldViPer]

I tried -30 curve right away and it's stable as rock with good results. Btw, at least my Asus Prime X570P have PBO / Curve Optimizer settings in BIOS so no need any external software.

[Zyll]

I thought the 5800x3d cannot be overclocked using PBO. Am I mistaken?

Zyll @ TAW

[coldViPer]

Correct, there is only PBO menu --> Curve Optimizer + other settings like PPT, TDC, EDC limit, PBO scalar etc. So no, I cant add +200MHz boost like before with my 5800X.

[edmuss]

I can't adjust anything via bios on my B450M, setting a windows task to run on boot to undervolt via pbo2tuner works fine though.

[Zyll]

Interesting, thanks for that info. Admittedly I don't quite understand undervolting to improve performance, it's always been overclock and overvolt for stability.

If you are undervolting for performance reasons, and not to keep the system cool and quiet, can you help explain for a caveman like me?

Zyll @ TAW

[edmuss]

The CPU thermally throttles above 77°C which reduces the clock speeds. Less voltage = less heat = consistently high clock speeds.

Because it's not overclocking you don't need the extra voltage to help the silicone run at the higher frequencies. A lot of modern hardware has the voltages set artificially high to ensure maximum stability across the massive range of system configurations they're likely to be in.

Basically by undervolting you're finding the lower limits that still retain stability with your machine; to some extents the silicone lottery still exists.

[Slammin]

A few reasons to undervolt are:

1. To decrease the amount of power your system uses.  Save the planet - Be Green.

2. Increase efficiency, usually of your GPU.  For instance, in the case of a 4090 GPU, restricting it to less than 100% power/voltage usage; you might limit it to use 80% power, while at the same time only reducing performance (FPS) by a much smaller factor (3 or 4 FPS or so).  These numbers are not exact but that is the principle.

3. Undervolting a CPU can actually increase performance.  The more power a CPU can grab, the more heat the CPU generates when loaded.  Once temp reaches a certain threshold, the CPU will throttle. Two ways to ensure the CPU will run at max clocks longer w/o throttling are employing excellent cooling, and/or undervolting.  The small risk of undervolting the CPU is the system can become unstable if the CPU is power starved.  Same with a GPU too, but a GPU crash due to undervolting presents almost no risk of a corrupted system whereas in a worst case scenario, a system crash from CPU undervolting can sometimes result in a crash that will require a total OS reinstall.  It's rare these days, but it can happen.

 

 

[coldViPer]

Offtopic: I also recommend this for GPU, undervolted my GPU from 1.08v to 0.875v, a tiny performance hit but much cooler now.

[VirusAM]

with the latest bios Asus added the option...so I have it set in BIOS now...just to let everyone known... -30 stable as rock

 

[Hartsblade]

4 hours ago, VirusAM said:

with the latest bios Asus added the option...so I have it set in BIOS now...just to let everyone known... -30 stable as rock

 

Which mother board are you using and can you post the bios version number please?

[Hiob]

4 minutes ago, Hartsblade said:

Which mother board are you using and can you post the bios version number please?

Just be aware, whilst a good MoBo and reliable Bios and good VRM can help with stability - how much you can bend the voltage curve is most of all a funtion of silicon lottery - aka the individual cpu. One may tolerate -30 all core, the next on the same MoBo only -15 or none at all.

[Hartsblade]

43 minutes ago, Hiob said:

Just be aware, whilst a good MoBo and reliable Bios and good VRM can help with stability - how much you can bend the voltage curve is most of all a funtion of silicon lottery - aka the individual cpu. One may tolerate -30 all core, the next on the same MoBo only -15 or none at all.

Thanks for the reminder. I've played around a little with voltage curves on my previous cpu. I'm just curious about his Asus mobo and bios because I have a Dark Hero and I'm pretty sure I have the most recent bios, but do not remember seeing a PBO or a Curve Optimizer for my 5800x3D.

[VirusAM]

Which mother board are you using and can you post the bios version number please?

Asus ROG b550-e bios version 1806.
I already used pbo2 tuner with -30 so it was no surprise to me.
Maybe I was lucky with the silicon

Thanks for the reminder. I've played around a little with voltage curves on my previous cpu. I'm just curious about his Asus mobo and bios because I have a Dark Hero and I'm pretty sure I have the most recent bios, but do not remember seeing a PBO or a Curve Optimizer for my 5800x3D.

I was not seeing it either, but it was in Asus specific options

[Hartsblade]

1 hour ago, VirusAM said:

Asus ROG b550-e bios version 1806.
I already used pbo2 tuner with -30 so it was no surprise to me.
Maybe I was lucky with the silicon I was not seeing it either, but it was in Asus specific options

Thanks, I'll take another look.

[Slammin]

Usually it will appear if you select Advanced in the PBO area. 

[Hiob]

2 hours ago, Hartsblade said:

Thanks for the reminder. I've played around a little with voltage curves on my previous cpu. I'm just curious about his Asus mobo and bios because I have a Dark Hero and I'm pretty sure I have the most recent bios, but do not remember seeing a PBO or a Curve Optimizer for my 5800x3D.

Since this is an enthusiasts MoBo I would really be startled if it wouldn’t allow CO for the 3D…

[Slammin]

Yeah, I wanted that mobo badly but it was never in stock back then.

[Hartsblade]

1 hour ago, Slammin said:

Yeah, I wanted that mobo badly but it was never in stock back then.

It took a lot of stalking of MicroCenter to get it back then.

[Hartsblade]

7 hours ago, Hiob said:

Since this is an enthusiasts MoBo I would really be startled if it wouldn’t allow CO for the 3D…

Did a little digging. Asus has not released the new bios for the Crosshair VIII mobos yet. Currently there is a beta version that includes the return of the curve optimizer, beta version 4303. Hopefully it will be officially released soon.

[RoboHackfeld]

I think everyone should try PBO -30. Most of the Mobos can handle this pretty good with the x3D, at least -20 should work.

If someone is running with MSI, with the newest Bios you can also activate Combo Strike within the UEFI. Where Mode 1 I guess is the same as PBO -10, 2 is -20 and 3 is -30.

Works with my X470 Gaming Plus MAX pretty good. Raised the Score in cinebench from 14k to 15k and temperatures fell from immideately 90°C to stable 73°C in Cinebench.

In DCS I really havent noticed a big impact in VR, because I think my 6900XT is bottlenecking but with lower tmperatures I fly a little more relaxed.

 

[Biggus]

I've been reading rumours that newer 5800X3Ds are needing more voltage as production continues, rather than less as has been the case with other Ryzen CPUs.  So it's not a given that you'll be able to set a given negative curve with a newer production example.

[Hiob]

1 hour ago, RoboHackfeld said:

I think everyone should try PBO -30. Most of the Mobos can handle this pretty good with the x3D, at least -20 should work.

 

Again, it is in the first place a property of the particular CPU if it can tolerate -30 or not. Also the -30 is CO (Curve Optimizer) and not PBO (CO is a/one feature of PBO2, but PBO itself is something different).

[Lange_666]

Mine runs stable at -30 across all cores.

[Dentedend10]

Hi,

I have this CPU, although on a Dell motherboard (Alienware prebuilt). I'm getting lots of stuttering within the cockpit, seems like the more complicated the plane, the more stuttering (F14 lots vs P51D none). 

FPSVR monitoring tells me that normally CPU frametime is around 12-14 ms, while around the carrier it gets up to 30 ms.

I've tried all kinds of optimizations to no avail. My best bet is still the CPU causing the stuttering (my GPU frametime is under 10 ms, GPu being always green, while CPU always having orange spikes, and completely red around the carrier).

Anyone with similar issues? I'm running DCS stable version.

Thanks