Ludicrous overclock slams 1.7 volts into 6700K in an attempt to stop CPU from bottlenecking an RTX 3080 — 5.2 GHz on aging four-core pushes GPU utilization from 60% to 74%

TrashBench
(Image credit: YouTube - TrashBench)

The Core i7-6700K was once one of Intel’s best CPUs for gaming, but fast forward to 2026, and the decade-old chip is now hardly an optimal choice to pair with any modern GPU hardware, including some entry-level graphics cards. Despite this, YouTuber TrashBench put the 6700K to the test and challenged himself to see if he could overcome CPU bottlenecking with an RTX 3080 purely through overclocking.

In his tests, the YouTuber pushed the Core i7-6700K to its absolute limit, exceeding safe voltage limits in an attempt to achieve his goal. Three overclocks were tested: a 4.7GHz overclock at 1.4v, a 5GHz overclock at 1.56v, and a 5.1GHz overclock at 1.65v. The YouTuber even attempted 5.2 GHz and 5.3 GHz overclocks with a vcore of 1.7 V, but sadly, neither attempt was successful. As for cooling, the 4.7GHz overclock was achieved with an air cooler, while the 5GHz and 5.1GHz overclocks were achieved using a custom loop submerged in an ice bath.

I Gave an Old CPU Max Volts to Feed a 3080 - YouTube I Gave an Old CPU Max Volts to Feed a 3080 - YouTube
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At stock speeds, the 6700K was barely able to get the RTX 3080 above 60% utilization in Cyberpunk 2077, with an average of 103 FPS. With the 4.7GHz overclock, the bottlenecking situation noticeably improved, with the RTX 3080 achieving nearly 70% utilization, resulting in 13% higher performance compared to stock. At 5GHz, the 6700K improved the RTX 3080’s utilization to 74%, with Cyberpunk 2077 performance improving by 17%. Finally, at 5.1GHz, the fastest overclock unfortunately yielded the least impressive result, improving performance by just 1 FPS compared to Cyberpunk 2077 running at 5GHz on the 6700K.

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The YouTuber also tested several other games featuring Shadow of the Tomb Raider, Hitman 3, and Far Cry 6. 3DMark Time Spy was also thrown in as a synthetic test. With air cooling at 4.7GHz, all of the aforementioned titles achieved an average performance gain of 7% compared to stock. In 3DMark Time Spy, the results were far different, with the 4.7GHz overclock achieving a whopping 19% performance improvement over stock. For the 5GHz ice-cooled results, performance improved by 11.3% on average over stock across the same three titles, and in 3DMark, the results showed a 24% improvement over stock.

The YouTuber unfortunately failed to achieve his goal of stopping CPU bottlenecking with a 6700K on an RTX 3080 through CPU overclocking alone. However, the overclocking results demonstrate that the Skylake flagship is still a capable gaming CPU, achieving around 100 FPS in all of the aforementioned games at 5 or 5.1GHz.

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Aaron Klotz
Contributing Writer

Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.

  • Vanderlindemedia
    That voltage could have been so much lower if he just used anything below subzero. Like a phasechange or so. On top of that, OC's should not be done with just bare CPU speeds but everything with it, FSB's, Memory speeds and such. In there is where the most gains are to be made.

    I pushed a 8350 for some time; running strong at 4.8Ghz with a 300MHz FSB. I was able to even reach 360Mhz but that gave such a weird number. It out pasted the far more expensive, 5Ghz model.
    Reply
  • hwertz
    A 3090? LOL. I had a GTX1650 in my Ivy Bridge (i5-3470) and the only thing I could get to hit 99-100% utilization was gravitmark (and any LLM/CUDA type workloads.) CP2077 I just enjoyed on high settings, it did a whole 30% on low but 80% on high with a 1 FPS drop in framerate (it was around 30FPS either way.) That was pre-2.0, CP2077 2.0 upped the requirements.

    I have it in a Coffe Lake (i7-8700) now and that can easily max out the card. (The Ivy Bridge is still running but as a media PC, the onboard video is fine for that use.)
    Reply
  • thestryker
    This is mostly a core count issue where the quads didn't age as well as everything else. My 6900K at 4.3 2c/4.2 8c had zero issues in CP2077 keeping my 3080 fed. HUB did some retrospective videos earlier this year and had the 2700X beating the 7700K in a current game list which didn't happen in games around their release.
    Reply
  • carocuore
    I remember when someone on a forum called me a moron for replying with "LOL" to his comment that said "the 6700K will be the last CPU releases in 25 years, it's THAT good, which is why I already preordered mine, there simply won't be another CPU that's faster than this" or something like that.

    He probably died when the 7700K was announced.
    Reply
  • usertests
    carocuore said:
    He probably died when the 7700K was announced.
    RIP In Processing. 🫡
    Reply
  • thestryker
    carocuore said:
    I remember when someone on a forum called me a moron for replying with "LOL" to his comment that said "the 6700K will be the last CPU releases in 25 years, it's THAT good, which is why I already preordered mine, there simply won't be another CPU that's faster than this" or something like that.

    He probably died when the 7700K was announced.
    That's funny, but also a little sad because decently priced 6-core HEDT already existed. Both HSW-E and BDW-E aged way better than their SKL and KBL desktop counterparts did despite being older architectures and on worse nodes. I want to say I paid about 35% more for my original 6800K setup (including motherboard) than if I'd gone with a 6700K. Well worth the price given that both my 6800K and 6900K systems are usable today and few games are CPU bottlenecked when used with a 6800 XT or 3080.
    Reply