Top positive review
5.0 out of 5 starsFantastic Card
Reviewed in the United States on October 23, 2023
This seems to be a fantastic card. My decade-old GTX 780 died and I ended up buying a used Powercolor Red Devil 6900 XT Unlimited which buzzed and whined and after a few days started crashing in games, stress tests, and benchmarks on default settings. Clearly the card was broken and I could not tell if the seller knew. I never buy used or open box (I'm not that lucky and too particular), so my bad. Next I bought a Sapphire 7800 XT from Newegg a month after they became available for the same price as the returned 6900 XT; somehow I stupidly missed that a 7800 XT generally outperforms the last-gen 6900 XT for less power consumption. Well, that went back without any use as I saw it was made in China and, when opening the box, found that characteristic toxic off-gassing, that makes my eyes water, throat burn, and head light, from nearly all Chinese-produced plastic and PCB these (this is not the case for other countries unless they're using some Chinese PCB in the housing, which is often the case). Finally, I snagged a "deal" on this reference card that would fit, by default, in the Monsterlabo fanless PC and that is made by TUL (Powercolor) and fabricated fully in Taiwan. It did not make me ill with toxic off-gassing (yes, everything off-gasses VOCs, but there are certainly levels of environmental contamination and toxicity). Powercolor made all of the reference AMD Radeon 7900 XT cards for the RDNA3 architecture this time regardless of which brand placed the sticker. This unit does not buzz, does not whine, I cannot even hear the fans at 1200RPM as was very audible with the Red Devil, requires only two eight-pin power connectors, and has very acceptable temperatures with the stock cooler (11C difference between hotspot and edge temperature with hotspot maxing out around 79C in my cool autumn room). Powercolor did an excellent job with the manufacture on this one and AMD did an awesome job on the architecture, with two caveats: These really should be much more energy efficient and should have been priced lower, ~$650 MSRP. Nvidia's anti-consumer greedy practices are keeping me from considering their weak and overpriced products this generation when I needed a new card, but they did a much better job on power efficiency and heat output. The 7900 XT overclocks as far as you provide it power and does not appear to love voltage, but for someone who wants to do the reverse of that, undervolt and underclock to save power, the RDNA3 architecture isn't very interested in doing so. Just to see what it could do, I allowed it 350watts and ran Unigine Heaven and it clocked itself up to 2900Mhz on the core which is insane. If I were to keep it cool and provide more power outside of AMD's parameters by modifying the board, I'm certain that clock would keep climbing eventually hitting at least 3,200-3,300Mhz. For my case, trying to reduce power draw even at lower clocks, the best I could was +15% Power Limit, 700mv (yes, that's right; the minimum on the bar), and 2350Mhz on the clock (2750Mhz and Fast Timing on the memory was no issue as with nearly every board out there does this fine). The card pulls ~250watts in Unigine Heaven 99-100% load, so ~60watts less than default settings and performs as well as stock (if stock values actually meant the card kept to 2400Mhz; they don't. It'll climb higher if it sees there is power and thermal headroom). This is also game stable so far. Raising the card even 15Mhz on these same power limitations or trying to reduce the Power Limit percentage results in lost performance or driver timeouts, though. Just lowering clocks on RDNA3 does not bring efficiency gains until you cut them 33-50% and that is not worth the performance cost!
I hope this helps someone! There is not much information out there about underclocking and undervolting these cards, so I learned through trial and error and hypothesizing on the data I am able to collect from the sensors as well as everything I learned from underclocking RDNA2 (which does not function the same as RDNA3!). RDNA4 high-end has been cancelled (as of now) and the planned mid-range release is supposed to focus on power efficiency, so we'll see what AMD can do when they try to improve in this area. Their CPUs do a very good job in comparison to Intel in performance-per-watt, but with the new GPU Chiplet architecture, there is probably a learning curve for power efficiency. Clearly the Chiplet architecture is amazing in raw clock speeds and rasterization performance. RDNA5 is on track and early results are very promising. We'll see if Nvidia can shape up and compete in the personal PC space or if they'll devote their energy to continuing growth in the highly profitable cloud and AI fields. I'd love to see Intel compete in the GPU space as well. Remember that being a company-cultist is in nobody's best interest, including yours, but ample competition helps drive lower consumer prices and greater innovation!