Overclock setting for Core i7 920 with air cooling and HT off, Aiming 4.2GHz

[Thales]

Hello everyone.

I like games such as Kerbal Space Program, Stormworks: Build & Rescue, Space Engineers..etc which are CPU bound, furthermore single core performance is especially important.

My system and benchmark: https://www.userbenchmark.com/UserRun/13638523

System:
Gigabyte GA-EX58-UD3R
Intel Core i7-920 D0
Palit Dual OC GTX 1080
Geil Plus 3x4GB DDR3 1600MHz CL9

PSU: Seasonic M12II 80+ Plus Bronze 750W
UPS: Tuncmatik Newtech Pro 1KVA Online

I see that single core performance of each new generation of CPUs are not being improved greatly. This reality prevents me to buy new system (MB, CPU and DDR4 rams). For example the best gaming CPU today, i9 9900k has 145pt single core performance according to https://cpu.userbenchmark.com/ . While in my benchmark test, my overclocked i7 920 @4.2GHz has 102pt single core performance. Buying new system (MB, CPU, Rams) is too costly for a 42% increase in single core performance I think. Though according to PassMark single core performance benchmark the difference between i9 9900k and my i7 920 is greater; around ~65% I believe. Which benchmark site or software do represent single core gaming performance more reliable?

After I explain my aim for overclock above, I want to show my overclock setting and ask questions about safety. I'm using core i7 920 since 2009. I bought Thermaltake Frio Advanced some years ago for overclock. I used it at 3.6GHz with HT on in the last year without touching voltages. This week I disabled HT and increased frequency to 4.2GHz (at 21X turbo). But I get bluescreen error so I increased voltages. Here is my setting:








I read that max Vcore voltage for i7 920 should be 1.375V. Is there anything I can do to reduce Vcore to 1.375V without getting bluescreen or reducing BCLK? I have not clear idea what should QPI/Vtt and DRAM voltages should be, but I increased them a bit nonetheless. Temperatures are ok, CPU barely goes above 80 at 100% load in Intel burn test thanks to the no hyperthreading.

Why CPUz shows different core voltage?
Is using 20x cpu clock ratio more stable than 21x?
What should QPI/Vtt and DRAM voltages?

My cpu is already 10 year old. So, using Vcore at 1.425V really bad idea or not? If my CPU dies can I use Xeon X5660 (and overclock) with my motherboard? I found that local dealers sell used Xeon X5660 for price ranging between 42$ to 55$.

 

[Mr.Scott]

I have X58A-UD3R
i7 930
on a 212+ Evo
3x2 OCZ Gold 1333
It is my daily machine.





Odd multi is a more favorable overclock.
Your vcore and QPI/VTT seems really high for the OC to me.

 

[Thales]

Thanks, I didn't know that odd/even difference.

Edit1: BCLK 199, Vcore 1.39V, QPI/Vtt 1.250. Now I'm running two intel burn tests. - BDOS
Edit2: BCLK 197, Vcore 1.40V, QPI/Vtt 1.275. Now I'm running two intel burn tests.

 

[Thales]

Highlighting question from the first post:

1. Which benchmark site or software do represent single core gaming performance more reliable?

2. Why CPUz shows different core voltage?
3. Is using 20x cpu clock ratio more stable than 21x?
4. What should QPI/Vtt and DRAM voltages?

5. If my CPU dies can I use Xeon X5660 (and overclock) with my motherboard?

 

[Mr.Scott]

1) Can't answer.
2) Because you still have the 'green' functions turned on. Eg: Turbo boost, C1E, EIST. Those usually get turned off when you overclock.
3) Answered. Odd is more stable.
4) Subjective to quality of CPU, memory, and board. I run 1.215v QPI/VTT and 1.65v on memory.
5) Yes on the Xeon. Be sure you're on the latest bios for your board.

 

[EarthDog]

Here's a good guide.... https://www.overclockers.com/3-step-guide-overclock-core-i3-i5-i7/

 

[Thales]

Thanks for the answers. I should read this guide first before asking questions.

2. Turbo boost turns ON if I use 21x clock ratio. Standard max clock ratio 20x.