AMD came back into the high-end PC graphics fold with the Radeon RX 6800, 6800 XT and 6900 XT boards late last year. Plagued by acute stock shortages and consequently inflated pricing instigated by etailers and scalpers alike, getting your hands on RDNA 2 hardware - even the cheaper RX 6700 XT - has been expensive and frustrating in equal measure.
Supply is very slowly catching up with demand, and it's to this background that AMD launches the Radeon RX 6600 XT. Built on a specific, smaller die and optimised for high-framerate 1080p gaming first and foremost, let's delve into the vital specs.
Premium Navi cards from AMD |
||||||
|---|---|---|---|---|---|---|
Radeon RX 6900 XT |
Radeon RX 6800 XT |
Radeon RX 6800 |
Radeon RX 6700 XT |
Radeon RX 6600 XT |
Radeon RX 5700 XT |
|
| Launch date | December 2020 |
November 2020 |
November 2020 |
March 2021 |
August 2021 |
July 2019 |
| Codename | Navi 21 |
Navi 21 |
Navi 21 |
Navi 22 |
Navi 23 |
Navi 10 |
| Architecture | RDNA 2 |
RDNA 2 |
RDNA 2 |
RDNA 2 |
RDNA 2 |
RDNA |
| Process (nm) | 7 |
7 |
7 |
7 |
7 |
7 |
| Transistors (bn) | 26.8 |
26.8 |
26.8 |
17.2 |
11.1 |
10.3 |
| Die Size (mm²) | 519 |
519 |
519 |
336 |
237 |
251 |
| Full Implementation of Die | Yes |
No |
No |
Yes |
Yes |
Yes |
| Hardware Raytracing | Yes |
Yes |
Yes |
Yes |
Yes |
No |
| Infinity Cache (MB) | 128 |
128 |
128 |
96 |
32 |
No |
| Compute Units | 80 |
72 |
60 |
40 |
32 |
40 |
| Processors | 5,120 |
4,608 |
3,840 |
2,560 |
2,048 |
2,560 |
| Texture Units | 320 |
288 |
240 |
160 |
128 |
160 |
| ROP Units | 128 |
128 |
96 |
64 |
64 |
64 |
| Boost Clock (MHz) | 2,250 |
2,250 |
2,105 |
2,581 |
2,589 |
1,905 |
| Game Clock (MHz) | 2,015 |
2,015 |
1,815 |
2,424 |
2,359 |
1,755 |
| Peak GFLOPS (SP) | 23,040 |
20,736 |
16,166 |
13,215 |
10,605 |
9,750 |
| Memory Type | GDDR6 |
GDDR6 |
GDDR6 |
GDDR6 |
GDDR6 |
GDDR6 |
| Memory Size (GB) | 16 |
16 |
16 |
12 |
8 |
8 |
| Memory Clock (MHz) | 16,000 |
16,000 |
16,000 |
16,000 |
16,000 |
14,000 |
| Memory Bus (bits) | 256 |
256 |
256 |
192 |
128 |
256 |
| Max Bandwidth (GB/s) | 512 |
512 |
512 |
384 |
256 |
448 |
| PCIe Support | Gen 4 x16 |
Gen 4 x16 |
Gen 4 x16 |
Gen 4 x16 |
Gen 4 x8 |
Gen 4 x16 |
| Power Connectors | 8+8 |
8+8 |
8+8 |
6+8 |
8 |
6+8 |
| TBP (watts) | 300 |
300 |
250 |
230 |
160 |
225 |
| GFLOPS per watt | 76.8 |
69.1 |
64.66 |
57.46 |
66.28 |
43.3 |
| Launch MSRP | $999 |
$649 |
$579 |
$479 |
$379 |
$399 |
Radeon RX 6600 XT Analysis
AMD uses what is known as the Navi 23 die for this card. Purposely designed for the mid-range segment, the 237mm² footprint and 11.1bn transistors is comfortably smaller than Navi 22 present on RX 6700 XT. Unlike previous generations where AMD has adopted a desktop-first strategy, this silicon is already present in the laptop-optimised Radeon RX 6600M GPU and will be present, in a similar form, on the infotainment systems in upcoming Tesla cars. How's that for a segue.
Back on track, there's nothing startling here. A reduction in transistors is met by commensurate cuts in horsepower. RX 6600 XT follows the same general configuration as other, more powerful Big Navi cards, so 32 compute units provide 2,048 shaders, an associated 128 texture units, and as there's one raytracing accelerator per CU, 32 of those, as well.
The biggest hit, arguably, is to the Infinity Cache, which drops from the 96MB present on the RX 6700 XT to just 32MB here. AMD says the card's 1080p sweetspot doesn't require a heap of Infinity Cache, but we have reservations because the board memory throughput is relatively weak. You see, this card carries a 128-bit bus allied to 8GB of GDDR6 memory operating at 16Gbps, leading on to only 256GB/s of potential bandwidth.
AMD also cuts the GPU-to-PC interface in half, to PCIe 4.0 x8, though this will not have much impact upon performance. Scaling down the die and power-burning components offers a 160W total board power. There is no Made By AMD reference board for this generation and we expect partners to release multiple models spanning the 160W-200W range. Hopefully most will make do with a single 8-pin power connector, though we're sure, in typical gusto, some will go for a 300mm board with dual 8-pin.
Potential Performance
We cannot provide our internal performance numbers for a little while. Up until then you'll have to do with some AMD-produced slides that paint the RX 6600 XT in a naturally favourable light.
With baked-in Smart Access Memory smarts, AMD reckons this new card is around 40 per cent quicker than the last-generation Radeon RX 5600 XT and around 15 per cent faster than rival GeForce RTX 3060 from Nvidia. In other words, it's considered an FHD120 or QHD60 card when all the bells and whistles are turned on. AMD says there are no crypto-related limiters on RX 6600 XT. Perusing the specs, particularly the memory, suggests its hash rate won't be stellar.
We have no major qualms with how AMD has gone about building this mid-range GPU - it has the necessary guts to hit the desired frame rate - but we're concerned that a mid-range card now starts at $379 (£349). Expect partner-overclocked model to begin at £400, assuming etailers don't charge a premium... and that figure feels rather expensive for a solution primed for 1080p. Looking back towards the Radeon RX 5700 XT, which came in at around $399, we can ask the question whether has AMD made enough performance and feature gains over the intervening two-year period?
Let's be clear, the state of affairs is such that AMD knows it will sell out of every card in quick-fire fashion because demand still vastly exceeds supply, and AMD, as a company, is all about maximising profit.
Partner cards will be available from August 11. What do you think? Does Radeon RX 6600 XT make sense at £350+? Let us know in the forums.
