Sunday, August 25, 2013

[Article] I give up. Have to settle at 4.3GHz with my 4770K.

In a previous post I mentioned that I was able to clock my new Haswell Core i7 4770K chip to 4.3GHz and I was planning to clock it to 4.4GHz. After trying for a week or so, I couldn't get it Prime stable at 4.4GHz below 1.3V Vcore. My CPU is a dog. It doesn't overclock well at all. In fact, it is a well below average chip. That's sad. I lost the silicon lottery.

But it is not the end. There is a few more tweaks I can do. For example, right now the RAM is at 1600MHz with XMP timings (9/9/9/24/2T/1.5V etc.) and cache ratio is at 39x with 1.075V. I think I can tweak the timings a bit and increase the cache ratio to 41x or so. 43x is ideal but will be a long shot  I guess. I would definitely have to increase the Un-core voltage to somewhere around 1.2V to get near 4.1GHz. But that doesn't add a lot of power so I should be alright. Maybe I could tweak the voltages a bit. Perhaps lower the CPU input voltage to cut the temps by a degree or two. I could even play with the BCLK as well. Perhaps put it to 105MHz with the multiplier dropped to 41x? That might improve the performance slightly. Something is better than nothing, right? 

Anyways, I am really disappointed with my CPU. There are people who have chips than can clock to 4.9GHz with just 1.25V. I have a great motherboard - a motherboard made for overclocking. But me not being able to get higher than 4.3GHz overclock is not the board's fault. It's the CPU alone. I probably can get by with 4.4GHz at something like 1.29V and be stable in real-world work loads. (Heck, I played Crysis 3 campaign from beginning to end with just 1.28V and didn't encounter a single crash). But in my head I know that it is not 100% stable and it might crash when I least expect it to. That is not something I can live with. Hey, it's just 100MHz which is even less than 2.5%.

One thing I should tell is that it was almost always the in-place Large FFT test that crashed when I tested for stability at 4.4GHz. Playing with the voltages other than the Vcore didn't made it more stable. It just needed more Vcore. When I kept on increasing the Vcore, the duration until Prime95 crashed lengthened, which means it was Vcore starved. 1.3V is a lot of volts for Haswell, no thanks to Intel cheaping out under the hood. Bastards!

Funny thing was that I could run 10 passes of Intel Burn Test at very high memory usage at 4.5GHz with just 1.280V Vcore. Intel Burn Test might be an indication of stability, but it is way inferior to Prime95, even though the temps while running Intel Burn Test is much higher than when running Prime95.

Here's are my current settings for 4.3GHz.
  • Vcore: 1.235V manually set in BIOS (1.248V max recorded in AISuite III)
  • Un-core multiplier: x39 (AUTO)
  • Un-core voltage: 1.075V manually set
  • RAM speed: 1600MHz
  • RAM timings: 9/9/9/24/2T
  • RAM voltage: 1.50V
  • Extreme Tweaking: Disabled
  • EPU Power Saving Mode: Disabled
  • Everything else: AUTO
Now, I haven't run adequate stress tests. I will do that after tweaking the un-core and the memory timings a bit.

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