As part of our Radeon RX 6600 XT launch coverage, we have reviewed the following cards: ASUS RX 6600 XT STRIX OC, MSI RX 6600 XT Gaming X, and Sapphire RX 6600 XT Pulse OC, XFX RX 6600 XT Merc 308

With the Radeon RX 6600 XT, AMD has launched a graphics card targeted at the masses of 1080p Full HD gamers out there. The goal was to provide decent performance that can handle all games at the highest details with Full HD—AMD has achieved that goal. Every single game in our test suite ran at least 60 FPS, most considerably higher.

Under the hood, the Radeon RX 6600 XT is powered by the Navi 23 silicon; AMD's smallest graphics chip of the RDNA 2 generation (so far) comes with 2,048 graphics cores, 64 ROPs, 128 TMUs, and 32 RT cores. Just like the other Navi 2x chips, Navi 23 is built on TSMC's 7 nanometer production process. One of RDNA 2's core improvements is the inclusion of a large Level 3 cache, which achieves impressive performance gains. On Navi 23, this cache is relatively small with just 32 MB (Navi 22: 96 MB, Navi 21: 128 MB). This is certainly a compromise to reduce the chip's die size and manufacturing cost, more on that later.

On average, across our 22-game strong test suite, we find the RX 6600 XT beating NVIDIA's RTX 3060 easily, with 14% better performance. Compared to the RTX 3060 Ti, it is 12% slower, though. AMD's last-generation flagship, the RX 5700 XT, ends up 8% slower than the 6600 XT. The generation-over-generation performance improvement compared to the RX 5600 XT is an impressive 35%. Last-generation cards from NVIDIA offer similar performance (RTX 2070S: -5%, RTX 2080: +1%, RTX 2080S: +5%). AMD's own RX 6700 XT is 16% faster than the RX 6600 XT.

If we look at higher resolutions, especially 4K, we can see that the RX 6600 XT falls behind quite a bit. The primary reason for that is that the L3 cache is rather small with just 32 MB, so it can't provide as much of a benefit as with 1080p. The ~10% penalty from 1080p to 4K relative to other cards is hence surprisingly large, but no issue at all. The RX 6600 XT is designed for 1080p and 1440p gaming, and the L3 cache performs very well here. The same goes for VRAM size. While the RTX 3060 non-Ti does offer 12 GB VRAM, it really has no effect at lower resolutions—AMD's 8 GB VRAM choice is the perfect amount.

In this review, we tested the XFX RX 6600 XT Merc 308, which is the company's flagship RX 6600 XT design variant. It comes overclocked to a rated boost of 2607 MHz out of the box, which is only a small increase over the AMD reference boost of 2589 MHz (+0.6%). In real-life, this turns into a 1% performance improvement at 1080p and 2% at 1440p and 4K. Other RX 6600 XT cards we tested don't do much better here. GPU manufacturers have gotten better and better at eking out the last bits of performance for the stock card, so additional factory overclocking potential is rather slim these days.

This makes the Radeon RX 6600 XT an excellent choice for Full HD gaming at the highest settings, possibly with refresh rates exceeding 60 Hz. The card will also handle nearly all titles at 1440p with 60 FPS. Raytracing performance is challenging, though. While the card has hardware-acceleration for RT, the performance hit is just too big to make this a viable card for 1080p raytracing as you'll drop well below 60 FPS in most titles. Here, NVIDIA definitely has the upper hand. The RTX 3060 and 3060 Ti are roughly twice as fast in raytracing due to additional hardware units. Even last generation's Turing RTX 2080 which offers similar non-RT FPS runs faster here. Still, this is definitely not a dealbreaker. AMD has recently released their FSR upscaling technology, which will cushion the performance hit from raytracing, and I'm not even sure if you absolutely must enable raytracing at this time to fully enjoy games—they are still developed for RT off; RT on is added at a later stage.

Visually, the XFX Merc 308 cooler looks fantastic. The company found the right balance between black and highlights without going overboard. I really like the matte paint and surface texture of the cooler shroud, which is among the best I ever touched, rivaling many metal coolers even though it's made out of plastic. Unlike other RX 6600 XT cards tested this week, XFX has decided to stick with standard PCIe slot height for their card, rather opting for a longer triple-fan design. In terms of noise levels, the RX 6600 XT Merc 308 can impress. When fully loaded, it reaches noise levels of only 24.5 dBA, which is whisper-quiet and basically inaudible when installed in a closed case or with other actively cooled components in your system. Our apples-to-apples heatsink comparison shows that the XFX heatsink is actually the weakest of all the RX 6600 XT heatsinks we tested, but only by a small margin. Still, this makes it achieving such low noise levels even more impressive. Compared to other, louder cards, the Merc 308 does run slightly higher temperatures, but 75°C under full load is perfectly fine in my opinion and definitely a reasonable compromise if you want to build a very quiet card. It's great to see that idle fan stop has become a standard capability nowadays—all Radeon RX 6600 XT cards that I know of, including the XFX Merc 308 in this review, will shut off their fans in idle, desktop work, and internet browsing.

XFX includes dual-BIOS capability with their card, but both BIOSes are 100% identical. While this provides a nice safety net if you want to mess around with BIOS flashing, it's also a lost opportunity. Nearly all vendors make some changes in the secondary BIOS, most of them creating a "quiet" BIOS for an easy-to-activate, software-free, OS independent option to adjust the card's operating parameters. Given the Merc 308 is already ultra-quiet at default, I would have set the fan curve on the second BIOS to be just a bit more aggressive to appeal to the people who prefer slightly lower temperatures and can live with the increased fan noise.

AMD shocked the world with the energy efficiency of Navi 21, which beats even NVIDIA's Ampere. The Radeon RX 6600 XT with its Navi 23 GPU is highly efficient, too, and can match Ampere nicely, which wasn't so easy for Navi 22 on the RX 6700 XT. Efficiency is similar to the RTX 3060 Ti and RTX 3070 even with the XFX factory overclock, which usually costs a little bit of efficiency. AMD isn't releasing a reference design card for the RX 6600 XT, so we have to base such estimates on the data available from custom designs, but it's close enough. With just 164 W, the XFX RX 6600 XT is very modest in its power requirements—any half-decent power supply will be able to handle it just fine.

What's surprising is that the Radeon RX 6600 XT does not support the full PCI-Express x16 interface, only x8. While I suspect this is a design choice that originated from laptops, where a wider bus isn't needed, desktops could definitely run into performance limitations when operating at x8. While it's certainly not a big deal for PCIe x8 4.0, running the Radeon RX 6600 XT in an older computer will have it operate at PCIe x8 3.0, which reduces the bandwidth significantly, resulting in a loss of a few percent in performance in general, with bigger losses and stuttering in specific games that move a lot of data across the bus.

Overclocking was alright on the XFX Merc 308. We gained 6% in real-life performance, which isn't as high as the top performers, but clearly better than the MSI Gaming X, which is held back by its power limit adjustment range. The differences between cards are small, though; I wouldn't base my buying decision purely on overclocking potential. The Radeon RX 6600 XT is in general constrained mostly by its power limit, so raising that is a must or you won't see any gains from overclocking. Memory overclocking is complicated a bit by the fact that these new memory chips have error correction, so finding the maximum OC involves more than just increasing the frequency and looking for rendering errors. What I'd like to praise AMD for is that they have significantly raised the overclocking limits in their Wattman OC driver interface. A huge issue in the past, they are now high enough for nearly all scenarios. Thanks, AMD!

AMD has announced an MSRP of $379 for the Radeon RX 6600 XT, which falls right between NVIDIA's MSRP for the RTX 3060 ($330) and RTX 3060 Ti ($400). If you've checked the graphics card market recently, you'll be aware that these prices are a pure fantasy and not realistic in any way. At this time, the RTX 3060 sells for $550, the 3060 Ti for $700, and the RX 6700 XT for $770. That's why I estimate the actual market price of RX 6600 XT to be around $650. AMD has clarified that supply for the RX 6600 XT will be "challenging," which means there's definitely not enough stock to get everyone a card, and I'm sure scalper bots are already refreshing sites across the web. In our Performance per Dollar section, I've plotted a few theoretical price points for the RX 6600 XT to give you a feel of what's a reasonable price and what's overpriced. The way things are currently, the RX 6600 XT at $400 would be too good to be true, $600 would be a good price, slightly better than the RTX 3060 and RTX 3060 Ti. Going far above that, for example $800, would make the card uncompetitive against other options, like the RTX 2080 and RX 5700 XT, which can be found for less than that. There's also some competition from the RX 6700 XT, which can currently be found for $770 and has higher performance.

According to XFX, the RX 6600 XT Merc 308 will sell for $410, a $30 increase over the AMD MSRP. Definitely not unreasonable, I'd be willing to pay that for the super-quiet cooler and beautiful design. XFX also offers the Qick 308 for $400, and the Swift 210 is targeted to hit the $380 MSRP. Given current market conditions I estimate that the Merc 308 will end up selling for around $680, $30 higher than the most basic cards. A bigger increase would be very difficult to justify because scalpers will happily sell you the RTX 3060 Ti for $700, and the RX 6700 XT for $770, which both offer higher performance. I also have to wonder where the budget cards are. Even $380 for a "x60" class card is a lot of money; wasn't there a time when you could buy a decent graphics card for gaming for $200?

I'm giving the XFX RX 6600 XT Merc 308 our "Recommended" award since it's a great RX 6600 XT card you should consider above others if you are in the market for an RX 6600 XT and can live with the currently inflated prices.