We have our first custom retail AMD Radeon RX Vega 64 GPU video card on the test bench in the form of the ASUS ROG STRIX RX Vega 64 O8G GAMING video card. ASUS has created a robust ROG STRIX version of RX Vega 64 with a factory overclock and overclocking ability in this air-cooled monster. Let’s see what it can do.


ASUS ROG STRIX RX Vega 64 O8G GAMING - Overclocking

Before you begin overclocking make sure you have the latest BIOS for this video card. The latest BIOS can be found here (Utilities/Version 2018/01/23 Vega64 1.47Mbytes.) If you have the latest BIOS it will just tell you it doesn’t need updating, if not, it will update it. We have applied this latest BIOS for our testing.

You will also want to grab the latest ASUS GPU Tweak II for overclocking. We are using version of the program.

Default Settings

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We are using the latest version of GPUz, 2.7.0, but it still only reports the highest DPM state, an internal clock speed of 1630MHz. Ignore this number, as we know ASUS has set the boost clock at 1590MHz and the base clock at 1298MHz. On the previous page we found the actual average clock speed is 1468MHz. This reported clock speed is a little confusing because as you can see even ASUS GPU Tweak II reports the 1630MHz number, which of course, is not really the case. The memory speed is being correctly reported at 945MHz however.

ASUS GPU Tweak II allows us to increase the Power Target to 150% from 100%, which is needed to allow a higher overclock. We can also increase the GPU Temp Target to 85c, though this isn’t needed. In terms of GPU Voltage, we can change the slider from 1200mv to 1350mv. We cannot change the memory voltage no matter what. With GPU Range Enhancement on we can change the GPU clock speed up to 3960MHz and the memory up to 6000MHz.

As you can see the voltage on our GPU rose up to 1.1625v on its own during normal gaming at default settings. The max GPU temperature was 76c and fan speed was 47% on automatic.

Highest Overclock

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Normally we first test overclocking without changing voltage, and then with voltage applied. However, with Vega 64 we found the highest overclock was best achieved with no voltage applied. When we raised voltage it just made the clock frequency more inconsistent and overall lower the higher we raised it. Voltage increases TDP and heat generation, and even with ASUS STRIX cooling this GPU just cannot take the highest voltages well.

Our highest overclock was to set the GPU clock to 1700MHz. Now remember, this isn’t actually 1700MHz, as you will see below we will show you the real-time clock speed which is a lot lower. When we tried 1710MHz, we had games lock up on us after a few minutes of gaming. At 1700MHz it was stable. On the memory side of things, we managed to push it to 1050MHz from 945MHz. That increases memory bandwidth to 537GB/sec versus 483GB/sec at default.

Without changing the voltage, you can see that AMD’s hardware voltage programming did raise the voltage anyway on us automatically. It hit 1.1750v, up from 1.1625v to allow this higher GPU frequency. Therefore, there is no need to raise GPU voltage, it is going to regulate it anyway.

One important note on this overclocking, the fans were running at 100% to ensure the highest overclock. At 100% fan speed it is loud. Outside of a case you probably would not want to run this while gaming due to the noise, but inside a case it may not be as bad, especially if you insulate well. At 100% fan speed the GPU hit 57c with this overclock.

In the grand scheme of overclocks, this is not that high of an overclock, and certainly not what we are used to from NVIDIA GPUs.

Highest Overclock GPU Frequency

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Here is the clock speed over time with this overclock. You will see the minimum clock speed is 1490MHz, up from 1427MHz before the overclock. The maximum is 1581MHz, up from 1514MHz before the overclock.

The overall average is now 1534MHz, which before the overclock it was 1468MHz.

Again, you can see we still are shy of the official boost clock of 1590MHz, even with the overclock! This overclock is on average 4.5% higher of a clock speed, or 66MHz average.

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The fan is at 100% fan speed here, but you can see with this overclock it reaches 57c and averages 51c.