Overclocking the R9 290X Explained & Results
Overclocking the R9 290X Explained & Results
In the realm of enthusiast graphics cards, a lot of focus is put upon a product’s ability to go above and beyond the call of duty. This means plenty of overclocking headroom for anyone that wants a quick, easy performance uplift without having to look at higher end solutions. For the R9 290X, AMD has taken a completely new approach to this time-honored tradition.
As we’ve explained on the previous pages, AMD’s PowerTune plays a huge part in the R9 290X’s performance since it balances out numerous different aspects in an effort to maximize performance. Judging from the temperature results, it’s also evident that the card is operating very close to its limits which, once again, is due to PowerTune’s effective management of its domain.
Since engine clocks, temperature and the board’s power limit are all tied closely at the hip, the folks on the Radeon team have decided that frequency overclocking alone is too one-dimensional. To expand upon that, they’ve moved away from the standardized clock speed sliders we’ve all been using and have instituted a form of percentage-based overclocking which ties the power limit to core speed. Essentially, both have to be modified at the same time with the final overclock ultimately being determined by PowerTune’s algorithms. This means a set frequency will only be achieved if PowerTune sees enough thermal and power overhead. If neither of those factors is deemed to be sufficient for a set frequency, clock speeds will be automatically dialed back accordingly.
Earlier in the review we talk about the capability to personalize the gaming experience offered by the R9 290X and the multicolored chart above is where that begins. With it, a gamer can set higher speeds and power limits for a performance boost or, if a game is performing well above their expectations, dial things back so the board uses less power and runs quieter. Alternately, the fan speed and Temperature Target sliders can be used in tandem to essentially cap performance at a given thermal limit.
The main issue we see is that AMD’s tools have no way of telling users exactly what effect their changes will have upon actual core frequencies regardless of their relationship to other aspects within PowerTune. The problem facing AMD is quite simple: with so many aspects of performance tied at the hip to power limits, temperatures and whatnot, it’s nearly impossible to predict the effect varied applications will have upon an requested overclock. We can respect that since we’ve seen many supposedly “stable” Kepler overclocks where a peak number was reported but never continually achieved since Boost had to dial things back to ensure the ASIC operated within its preset boundaries. So AMD erred on the side of caution and is using what boils down to best-case percentages. Set them, keep a close eye on things and cross your fingers.
At first this whole process may seem a bit contrived but it actually works quite well in both Silent and Uber modes once you get the hang of it. As a rule of thumb, we moved towards the higher end of the spectrum (that’s what overclocks are for, right?) but the end results weren’t all that great. Even with fan speeds set to a screaming 70% the core speed hit a constant 1115MHz which isn’t all that bad and GDDR5 clocks hit 5684MHz before plateauing.
Unfortunately, when the RPMs were dialed down to a slightly more pedestrian 55%, overclocking was next to impossible with PowerTune constantly clamping down and returning frequencies to their default values after a few minutes. The R9 290X obviously rewards cooler temperatures with higher performance and that bodes well for board partners’ versions (which are due out before the end of November).
In reality, PowerTune’s new behavior may favor overclockers but may also allow them to post completely unrealistic results. Due to the lack of sustained load in programs like 3DMark, ultra high frequencies are ultimately quite achievable since the core will only be operating at its maximum frequency for short periods of time, followed by a cool-down period as the next benchmark loads. This allows the R9 290X to neatly sidestep the thermal limitations that start popping up as it remains under load. While our results are considered fully “gaming stable”, don’t expect every overclocking achievement to adhere to the same set of rules.
With all of that in mind, we don’t believe the R9 290X is a particularly good overclocker from a gamer’s perspective since its achievable, long-term clock speeds are typically lower than what you may have set.
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