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AMD Radeon RX 6900 XT Review - The Biggest Big Navi

W1zzard

on Dec 8th, 2020,

in Graphics Cards.

Manufacturer: AMD

Value & Conclusion »

Overclocking

GPU-Z Screenshot for Overclocked Graphics Card

Overclocking the RX 6900 XT is similar to the RX 6800 XT in that you must increase the power limit. By default, the card runs into its power limit all the time, which constrains the clocks—any additional overclock will not yield higher frequencies. Once you've dialed up the power limit, overclocking works very well.

AMD has raised the overclocking limit for the maximum GPU frequency to 3000 MHz, which sure is nice, but highly unlikely to be achieved. My card topped out at 2810 MHz boost, so there is plenty of headroom; maybe they should have raised the memory limit instead, or just removed those limits completely.

I also figured out how to get 100 MHz higher memory clock. By default, the "VRAM Tuning" section gives you a slider that's percentage based, going up to 107%. Maxing that out will clock memory at 2140 MHz (2000 MHz * 1.07). When you switch to "Advanced Control," you get a slider that's MHz based and goes up to 2150 MHz, or 107.5%.

What's REALLY surprising here is that the ASUS STRIX 6800 XT at maximum OC is significantly faster than the AMD RX 6900 XT at maximum OC. It looks as though the AMD power limit is still too low after the manual increase, so the card can't clock as high as the ASUS card, which has a higher power limit.

Maximum Overclock Comparison
	Avg. GPU Clock	Max. Memory Clock	Performance
AMD RX 6800	2472 MHz	2140 MHz	197.2 FPS
AMD RX 6800 XT	2322 MHz	2140 MHz	219.8 FPS
AMD RX 6800 XT @ Max Power Limit	2572 MHz	2140 MHz	235.5 FPS
AMD RX 6900 XT	2434 MHz	2150 MHz	237.6 FPS
ASUS RX 6800 XT STRIX OC LC	2743 MHz	2140 MHz	248.5 FPS
PowerColor RX 6800 XT Red Devil	2563 MHz	2140 MHz	235.1 FPS
Sapphire RX 6800 XT Nitro+	2622 MHz	2140 MHz	237.5 FPS