The RX 6900 XT has the same 300W TBP (Total Board Power) rating as the RX 6800 XT. Using our Powenetics equipment, we've logged power, GPU clocks, temperatures, and fan speeds while looping Metro Exodus at 1440p ultra five times (without ray tracing or DLSS). We also test with FurMark running at 1600x900 in a window using the stress test mode.
Separate from the power testing, we also check noise levels at a distance of 15cm from the graphics card (in an open case). At idle, our PC’s noise floor is 46.0 dB — that's with the GPU fans not spinning, in Zero dB mode. After running Metro for 15 minutes, the RX 6900 XT noise levels were 47.7 dB. That's actually slightly quieter than the RX 6800 XT, which, as we'll see in a moment, appears to be due to differences in the default fan curve.
Clock speeds, temperatures, fan speeds, and power are all interrelated. Drop the clocks, and you reduce the power and temperature. Raise the fan speed, and you reduce the temperature and maybe even power use, potentially allowing for higher clocks. We used AMD's built-in Radeon Settings utility to adjust the fan speeds and other settings on the overclocked card, for example, producing the results seen here.
Like several of Nvidia's latest GPUs, the RX 6900 XT uses just a bit more power than the official TDP rating. Overclocked, it's right up with the RTX 3090 and actually surpasses it in FurMark (by a whole 4W). It's not a big deal, and we suspect a lot of users buying the 6900 XT will end up using Rage Mode since it's basically a free overclock that just raises the power limits.
As we saw with the RX 6800 and 6800 XT, AMD has now started to be a bit more conservative in its official boost clock figures. All of the RX 6000 GPUs have exceeded their boost clocks in our Metro Exodus testing, and we definitely noticed other games going above 2250 MHz. Overclocked, the card even managed a cool 2.5 GHz, which is pretty freaking awesome. We can't wait to see what the extreme overclockers fare with liquid nitrogen.
Temperatures for the RX 6900 XT are okay, though it does end up at the top of our range in stock operation. What's interesting is that the fan speed is actually lower than the RX 6800 XT (see below), so AMD has apparently applied a different fan profile here that favors low noise levels over temperatures. Our overclocking tosses that out the window, of course, and the 6900 XT goes from being one of the quietest but warmest GPUs to having the highest fan speed and lowest temperatures.
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