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Stress Testing OC Setup/Prime95 Questions

Hi folks,

 

What's the best way to go about stress/thermal-testing a CPU overclock these days?

 

I just did a fresh WC loop, and I wanted to make sure it was effective; no need to re-seat CPU cooler, appropriate amount of TIM, etc. I've been running Prime95 on the Small FFT setting to try and cook the CPU. Is this still a good indicator of both the loop's effectiveness and system stability?

 

On the OCing side of things, I've also read that Prime95 will alter your voltage to suite it's demands from your OC preset. I locked out voltage changes in bios. Will it override this anyway, ie. am I seeing the CPU stress-tested at the voltages I set, or the voltages Prime95 demands?

 

Matt

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34 minutes ago, Cavalry Canuck said:

Hi folks,

 

What's the best way to go about stress/thermal-testing a CPU overclock these days?

 

I just did a fresh WC loop, and I wanted to make sure it was effective; no need to re-seat CPU cooler, appropriate amount of TIM, etc. I've been running Prime95 on the Small FFT setting to try and cook the CPU. Is this still a good indicator of both the loop's effectiveness and system stability?

 

On the OCing side of things, I've also read that Prime95 will alter your voltage to suite it's demands from your OC preset. I locked out voltage changes in bios. Will it override this anyway, ie. am I seeing the CPU stress-tested at the voltages I set, or the voltages Prime95 demands?

 

Matt

I use Asus Real Bench: https://rog.asus.com/rog-pro/realbench-v2-leaderboard/

 

If it passes 8 hours of that and an overnight AIDA64 default and AIDA FPU only runs... your probs fine :)

Rig: i7 13700k - - Asus Z790-P Wifi - - RTX 4080 - - 4x16GB 6000MHz - - Samsung 990 Pro 2TB NVMe Boot + Main Programs - - Assorted SATA SSD's for Photo Work - - Corsair RM850x - - Sound BlasterX EA-5 - - Corsair XC8 JTC Edition - - Corsair GPU Full Cover GPU Block - - XT45 X-Flow 420 + UT60 280 rads - - EK XRES RGB PWM - - Fractal Define S2 - - Acer Predator X34 -- Logitech G502 - - Logitech G710+ - - Logitech Z5500 - - LTT Deskpad

 

Headphones/amp/dac: Schiit Lyr 3 - - Fostex TR-X00 - - Sennheiser HD 6xx

 

Homelab/ Media Server: Proxmox VE host - - 512 NVMe Samsung 980 RAID Z1 for VM's/Proxmox boot - - Xeon e5 2660 V4- - Supermicro X10SRF-i - - 128 GB ECC 2133 - - 10x4 TB WD Red RAID Z2 - - Corsair 750D - - Corsair RM650i - - Dell H310 6Gbps SAS HBA - - Intel RES2SC240 SAS Expander - - TreuNAS + many other VM’s

 

iPhone 14 Pro - 2018 MacBook Air

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On 11/23/2020 at 10:57 PM, LIGISTX said:

I use Asus Real Bench: https://rog.asus.com/rog-pro/realbench-v2-leaderboard/

 

If it passes 8 hours of that and an overnight AIDA64 default and AIDA FPU only runs... your probs fine :)

Thanks for your reply!

 

It appears to be stable at 4.8Ghz, 1.275v vcore setting. I feel like I could coax more out it, but the bios won’t let me go above 1.299v. The jury seems mixed on whether or not it’s a good idea to run above 1.3v on a Haswell/Devil’s Canyon chip. Are there other settings I need to play with to open up the option of more voltage?

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15 hours ago, Cavalry Canuck said:

Thanks for your reply!

 

It appears to be stable at 4.8Ghz, 1.275v vcore setting. I feel like I could coax more out it, but the bios won’t let me go above 1.299v. The jury seems mixed on whether or not it’s a good idea to run above 1.3v on a Haswell/Devil’s Canyon chip. Are there other settings I need to play with to open up the option of more voltage?

I don't know why it wouldn't allow more voltage.... BIOS usually lets you set just about anything, even if the voltage will for sure fry your chip.

 

Either way. 4.8 GHz on haswell is pretty damn quick, so honestly if its stable, your likely fine. I had a 4770k @ 4.4, no recollection of what the voltage is. I want to say 1.25 but I genuinely do not remember, and that was on liquid metal and a custom loop. It likely had more in it as well, but eh. Soon after I got a 6700k that I still have, 4.6 GHz at I think also about 1.25...... But point is, a 4770k @ 4.8 is not all that much slower than say a 7700k @ 4.8. That is still a solid CPU, and trying to get 4.9 or maybe 5 would not really result in much difference anyways.

 

I would see if you can get it stable at any lower volts, and if not, call it good :)

Rig: i7 13700k - - Asus Z790-P Wifi - - RTX 4080 - - 4x16GB 6000MHz - - Samsung 990 Pro 2TB NVMe Boot + Main Programs - - Assorted SATA SSD's for Photo Work - - Corsair RM850x - - Sound BlasterX EA-5 - - Corsair XC8 JTC Edition - - Corsair GPU Full Cover GPU Block - - XT45 X-Flow 420 + UT60 280 rads - - EK XRES RGB PWM - - Fractal Define S2 - - Acer Predator X34 -- Logitech G502 - - Logitech G710+ - - Logitech Z5500 - - LTT Deskpad

 

Headphones/amp/dac: Schiit Lyr 3 - - Fostex TR-X00 - - Sennheiser HD 6xx

 

Homelab/ Media Server: Proxmox VE host - - 512 NVMe Samsung 980 RAID Z1 for VM's/Proxmox boot - - Xeon e5 2660 V4- - Supermicro X10SRF-i - - 128 GB ECC 2133 - - 10x4 TB WD Red RAID Z2 - - Corsair 750D - - Corsair RM650i - - Dell H310 6Gbps SAS HBA - - Intel RES2SC240 SAS Expander - - TreuNAS + many other VM’s

 

iPhone 14 Pro - 2018 MacBook Air

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14 hours ago, LIGISTX said:

I don't know why it wouldn't allow more voltage.... BIOS usually lets you set just about anything, even if the voltage will for sure fry your chip.

 

Either way. 4.8 GHz on haswell is pretty damn quick, so honestly if its stable, your likely fine. I had a 4770k @ 4.4, no recollection of what the voltage is. I want to say 1.25 but I genuinely do not remember, and that was on liquid metal and a custom loop. It likely had more in it as well, but eh. Soon after I got a 6700k that I still have, 4.6 GHz at I think also about 1.25...... But point is, a 4770k @ 4.8 is not all that much slower than say a 7700k @ 4.8. That is still a solid CPU, and trying to get 4.9 or maybe 5 would not really result in much difference anyways.

 

I would see if you can get it stable at any lower volts, and if not, call it good :)

Sorry, I never did say what my CPU was! I have a 4790k. Since I last posted I managed to figure it out. I had my ring voltage on a manual setting (1.7v) and it wouldn't let me move them closer than 0.4v.

 

Anyway, I managed to get it stable at 4.9, 1.325vcore. But the temps on one of the cores was causing it to throttle on Prime95. It was stable and solid on AIDA64, with dramatically lower temps (highest core was 82). Regardless, I dialed it back to 4.8, and the lowest stable voltage I managed to find for that is 1.265. Managed to get my RAM back up to the specs it shipped with without causing crashes.

 

I have a couple additional questions if you are willing to entertain them. To keep the ram stable, I have it set to the stock spec voltage of 1.65v. Are there any CPU voltages I will need to adjust or keep an eye on because of this? Like, if I manually set the vccin to 1.7v, will that cause any issues or risk breaking things? 

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1 hour ago, Cavalry Canuck said:

Sorry, I never did say what my CPU was! I have a 4790k. Since I last posted I managed to figure it out. I had my ring voltage on a manual setting (1.7v) and it wouldn't let me move them closer than 0.4v.

 

Anyway, I managed to get it stable at 4.9, 1.325vcore. But the temps on one of the cores was causing it to throttle on Prime95. It was stable and solid on AIDA64, with dramatically lower temps (highest core was 82). Regardless, I dialed it back to 4.8, and the lowest stable voltage I managed to find for that is 1.265. Managed to get my RAM back up to the specs it shipped with without causing crashes.

 

I have a couple additional questions if you are willing to entertain them. To keep the ram stable, I have it set to the stock spec voltage of 1.65v. Are there any CPU voltages I will need to adjust or keep an eye on because of this? Like, if I manually set the vccin to 1.7v, will that cause any issues or risk breaking things? 

Oh man, I don't remember DDR3 RAM settings at all. I know if you try 1.65v on DDR4 your asking for a horrible time though. lol. I just don't remember man...... Likely some really in depth threads on extremeOC forum about DDR3 overclocking and such though.

Rig: i7 13700k - - Asus Z790-P Wifi - - RTX 4080 - - 4x16GB 6000MHz - - Samsung 990 Pro 2TB NVMe Boot + Main Programs - - Assorted SATA SSD's for Photo Work - - Corsair RM850x - - Sound BlasterX EA-5 - - Corsair XC8 JTC Edition - - Corsair GPU Full Cover GPU Block - - XT45 X-Flow 420 + UT60 280 rads - - EK XRES RGB PWM - - Fractal Define S2 - - Acer Predator X34 -- Logitech G502 - - Logitech G710+ - - Logitech Z5500 - - LTT Deskpad

 

Headphones/amp/dac: Schiit Lyr 3 - - Fostex TR-X00 - - Sennheiser HD 6xx

 

Homelab/ Media Server: Proxmox VE host - - 512 NVMe Samsung 980 RAID Z1 for VM's/Proxmox boot - - Xeon e5 2660 V4- - Supermicro X10SRF-i - - 128 GB ECC 2133 - - 10x4 TB WD Red RAID Z2 - - Corsair 750D - - Corsair RM650i - - Dell H310 6Gbps SAS HBA - - Intel RES2SC240 SAS Expander - - TreuNAS + many other VM’s

 

iPhone 14 Pro - 2018 MacBook Air

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