ASUS ROG STRIX X299-E Gaming Review


  • Author: MAC
  • Date: September 27, 2017

Auto & Manual Overclocking Results

Though it might feature a new socket, this LGA2066 platform is still fundamentally identical to the LGA2011 series that came before it when it comes to overclocking. Much like Broadwell-E, the new Skylake-X processors are still based on a 14nm process, so you can definitely still theoretically use up to 1.35V CPU core voltage pretty safely. However, that only applies to the i7-7800X and i7-7820X. When it comes to the i9-7900X you can’t use that much voltage given the incredible amount of heat it outputs when overclocked and overvolted. Personally, even with an absolutely top-notch dual-fan air cooler or high-end dual-fan AIO we wouldn’t recommend more than 1.25V, and even that much voltage will be problematic for most cooling solution. In order to avoid creating extra heat, we also recommend being conservative with the other system voltages, namely the cache/mesh voltage, the system agent voltage (VCCSA) and the I/O voltage (VCCIO). Ideally, you shouldn’t need to apply more than 1.15V to the cache/mesh while still being able to reach a ~3200MHz frequency, while near default VCCSA and VCCIO values of 0.95V and 1.05V should allow you to reach memory speeds of up to DDR4-3733.

The rules for Kaby Lake-X are unsurprisingly similar to mainstream Kaby Lake. Our personal pointers are to increase the vCore up to around 1.35V if you’re cooling can handle it, while increasing the VCCIO up to 1.20V, and the System Agent voltage up to 1.25V if you plan on increasing the cache or memory frequency. If you are trying to achieve the highest possible DDR4 memory speeds, increasing the VCCIO to 1.30V and vSA to 1.35V might be worth trying out. These last two are really only needed if you plan on seriously pushing the uncore/cache frequency or the memory frequency.

All of the LGA2066 processors are multiplier and BCLK unlocked, but unless you’re trying to extract every last megahertz there’s no reason to go crazy increasing the BCLK above 103-105Mhz since you can achieve similar results by just tweaking the various multipliers instead.

Lastly, we highly recommend that you avoid stress testing Skylake-X with the latest build of Prime 95. The simple fact of the matter is that due to its use of AVX its puts an entirely unrealistic load on the CPU, which causes both CPU and VRM temperatures to skyrocket until one or the other will start throttling. If you aim for Prime 95 stability/temperatures you will be robbing yourself of hundreds of megahertz of overclocking potential.

Auto Overclocking

Like many previous ASUS motherboards, the STRIX X299-E features two types of automatic overclocking. There is the TPU option that you can find in the UEFI BIOS and the 5-Way Optimization feature that is located in the Ai Suite III utility. The BIOS-based option relies on presets and it is quite simple since it only offers two choices, TPU I or TPU II. TPU I applies an overclocking preset that is designed for those with air cooling, while TPU II is a more aggressive option for those with liquid cooling.


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In practice, TPU I clocked our i9-7900X to 4.5Ghz @ 1.211V for 1-4 thread workloads, and 4.3Ghz at 1.195V during more highly threaded workloads. The AVX-512 frequency was limited to 4.1GHz. Selecting the TPU II option provided a slight improvement, pushing our i9-7900X to 4.6Ghz at 1.211V during lightly threaded workloads, and 4.4Ghz at 1.234V in more thread-intensive applications. The AVX-512 frequency was similarly bumped up to 4.3GHz. Both settings set the cache/mesh to 2700MHz – up from 2400MHz – while the memory speed was bumped up to a respectable DDR4-3200 14-14-14. We were using a G.Skill DDR4-3200 14-14-14 memory kit so clearly the XMP preset was applied. This BIOS-based automatic overclocking option is very fast – just the time it takes to save & exit the BIOS – and as you can see it produces some pretty solid results given the limitations of the nuclear reactor known as the Core i9-7900X. Speaking of which, don’t make the mistake of thinking that the above settings are conservative and easy to cool. In non-AVX but still fully loaded synthetic workloads, core temperatures still hovered in the 90-100°C range with either a Corsair Hydro H110i or Prolimatech Mega Shadow, both with fans at full speed. To put it simply, this 10-core chip is an absolute nightmare to cool.

When it came time to test the cool-running Core i7-7740X, we didn’t want to waste our time with TPU I, so we went straight to TPU II which pushed our chip all the way up to 5.0GHz at 1.30V – no matter the workload – left the uncore/cache frequency untouched, and applied our memory kit’s XMP profile. Can complain with any of that, an awesome performance boost in an instant.

As mentioned above, within the Ai Suite III utility there is the 5-Way Optimization automatic overclocking feature. While this feature also makes use of the TPU – which stands for TurboV Processing Unit – it is regarded as an intelligent approach to automatic overclocking because it does not rely on presets. Instead, it slowly increases your processor’s clock speed and voltage, tests for stability, monitors fan speeds and temperatures, and repeats until it has found the sweet spot. Nowadays, you can even specify a clock speed to start from and even what maximum temperature you feel comfortable with.

With all of that said, let’s see what 5-Way Optimization was capable of:


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Since we are always aggressive when it comes to overclocking, we selected the TPU II and Extreme Tuning options applied to all cores. As you can see above, the results are exactly the same as when using the BIOS-based TPU II setting. Despite the fact that we selected the “all cores” option, our i9-7900X would nevertheless jump to 4.6GHz in lightly-threaded applications, perhaps due to the Turbo Boost Max 3.0 feature.

The i7-7740X overclock was ultimately also identical – after failing to stabilize the system at both 5.1Ghz and 5.2GHz levels – so forgive us for not wanting to needlessly re-run all of the benchmarks/stress tests.

Manual Overclocking

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As we have come to expect from an ASUS ROG motherboard, our manual overclocking efforts were – thankfully – easy and uneventful. In the end, we were able to push the Core i9-7900X to 4.7GHz with our self-imposed 1.25Vcore limit. With an eye towards further managing temperatures, we also set a -1 AVX offset and a -2 AVX-512 offset, which limits the cores to 4.6GHz and 4.5GHz when those particular extensions are used. When it came time to overclock the cache/mesh and memory, we simply set the cache voltage to 1.15V, system agent voltage to 0.95V and the I/O voltage to 1.02V. This allowed us to increase the cache/mesh frequency from 2400MHz to 3200MHz – which provides a VERY nice performance boost – and we overclocked the memory from DDR4-3200 14-14-14 to DDR4-3733 16-16-16. We could have likely pushed the memory much higher, but since we are already tickling the 100GB/s memory read bandwidth mark, more is not really necessary.

Our dainty little Core i7-7740X proved its high frequency capabilities by hitting 5.2GHz with a relatively conservative 1.35V. The temperatures were still very manageable – somewhere in the low 70°C range – so 5.3 or 5.4GHz is certainly not outside the range of possibility for those willing to give it some additional voltage. The uncore/cache hit a wall at modest 4400MHz with 1.35VCCSA and 1.300VCCIO, but on the plus side we were able to push our memory kit all the way up to DDR4-4000, albeit with fairly loose timings.

Overall, overclocking on this motherboard was a problem-free experience. Even despite the monstrous power demands of our overclocked Core i9-7900X we never felt the need to baby the motherboard or give it any active cooling. We are now a full three months after launch day, so there’s been ample UEFI updates and all the kinks appear to have been ironed out (Prime95 VRM load aside). Obviously, the automatic overclocking results speak for themselves, they are as high as you could possibly want on either of these processors…and even perhaps higher than you can reasonably cool in the case of the Skylake-X chip.

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