re: PC Discussion - Gaming, Performance and Enthusiasts

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Are you plan on delidding? Those temps aren't too high but have you found a stable voltage for 4.5GHz yet?

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You got some catching up to do. I posted this last night:

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UPDATE:

4.6GHz @ 1.26v. Prime95 blend test, goes through the first set of 10 tests, temps hovering at 60-65 on the hottest core.

Then, the second set of tests starts... within a minute, I see 85, then 90, then 95. I see slight throttling at that point, then BSOD.

Googling more about Haswell stability tests, I read several guides recommending aida64 instead. Never used it before. I downloaded it and ran a stress test. Temps were in the 60 and 70s (but fluctuated A LOT and often). Ran for maybe half an hour, no super huge heat increase like what Prime had caused when kicking it up a notch.

After some more messing around, I got a 4.7GHz stable OC at 1.3v, and AIDA64 temps were fluctuating madly but hovered in the 70s.

So I think I'll stay with this overclock and see how temps look in games, compressing, encoding, and maybe even folding.

Definitely a hot motherfricker. But from what I've read, it appears that I have at least an above average chip. One guide mentioned that the baseline for seeing if you have a "good" Haswell is to set your vcore a 1.25 and see if you can boot to desktop at 4.5GHz. I can, and it's stable.

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Then I posted:

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So, with my current OC of 4.7GHz, the CPU gets to be about 70C in "normal" full-load situations. I'll probably still delid. I think the hammer and vise method looks the safest (despite how bad it may sound). If you've never seen that method, you basically use a stable vise to grip the IHS, then set a block of wood against the PCB and gently hammer it. No blades ever touch it.

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So basically, I have what I deem a "real-world" rock-solid stable 4.7GHz overclock. I think with a delid I can get to 5.0+ with the same caveats.

Aside from the heat, overclocking the Haswell is awesome. You can now set the L3 Cache/Ring frequency and voltage separately from the CPU frequency and vcore. You have to find that sweet spot to get an optimal CPU clock at the lowest temp, but at the same time you can let your L3 clock and voltage lag behind (reducing heat and increasing stability) just enough so that it won't be your bottleneck.

You can also leave BCLK alone and, like the X79 platform, mess with the BCLK strap to achieve the same clocks at lower multi (the multiplier seems to affect temps more than vcore to a certain extent). I haven't messed with this yet, but soon.

Oh, and it seems like memory clock is even less important in Haswell. At stock, Haswell's integrated memory controller will let you run some pretty ridiculous memory clocks, but once you start overclocking the CPU, that capability gets reduced pretty quickly it seems. You probably won't get a 4.7GHz overclock AND 2133Mhz memory. Little bit of a trade-off vs. Ivy. But it doesn't matter to me. Mem speed doesn't matter nearly as much as CPU clocks, so I just set my DDR3 1600 XMP and moved on.