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Review: Sapphire Radeon RX 5600 XT Pulse OC

by Tarinder Sandhu on 21 January 2020, 14:01

Tags: AMD (NYSE:AMD), Sapphire

Quick Link: HEXUS.net/qaehqm

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Introduction

AMD brought renewed focus to the premium end of the discrete graphics card market in the summer of 2019 with Navi-infused Radeon RX 5700 XT and RX 5700 GPUs now priced from £330 and £300, respectively. Battling against rival GeForce RTX 2060/2060 Super and 2070 GPUs from Nvidia, AMD's performance duo continues to give a solid performance account.

But it's not the £300-plus market that is important for high-volume sales. To that end, AMD released the Radeon RX 5500 XT, priced from £160 and mixing it up with the GeForce GTX 1650 Super/1660/1660 Super.

The clear pricing chasm between Navi-based cards is clear to see. This is why, as fully expected, AMD now populates the £250-plus segment with a new GPU. Enter the Radeon RX 5600 XT.

AMD's mainstream GPU line-up

 
Radeon RX 5700 XT
Radeon RX 5700
Radeon RX 5600 XT
Radeon RX 5500 XT
Radeon RX Vega 56
Radeon RX 580
Launch date
Jul 2019
Jul 2019
Jan 2020
Dec 2019
Aug 2017
Apr 2017
Codename
Navi 10
Navi 10
Navi 10
Navi 14
Vega 10
Polaris 20
Architecture
RDNA
RDNA
RDNA
RDNA
GCN
GCN
Process (nm)
7
7
7
7
14
14
Transistors (bn)
10.3
10.3
10.3
6.4
12.5
5.7
Approx Die Size (mm²)
251
251
251
158
486
232
Shaders
2,560
2,304
2304
1,408
3,584
2,304
Texture Units
160
144
144
88
224
144
ROP Units
64
64
64
32
64
32
Boost Clock (MHz)
1,905
1,725
1,560
1,845
1,471
1,340
Game Clock (MHz)
1,755
1,625
1,375
1,717
-
-
Peak SP TFLOPS
9.75
7.95
7.02
5.20
10.54
6.17
Memory Type
GDDR6
GDDR6
GDDR6
GDDR6
HBM2
GDDR5
Memory Size (GB)
8
8
6
4 / 8
8
4 / 8
Memory Clock (MHz)
14,000
14,000
12,000
14,000
800
8,000
Memory Bus (bits)
256
256
192
128
2,048
256
Max Bandwidth (GB/s)
448
448
288
224
410
256
PCIe Support
Gen 4
Gen 4
Gen 4
Gen 4
Gen 3
Gen 3
Power Connectors
6+8
6+8
8
8
8+8
6
TDP (watts)
225
180
150
130
210
185
Launch MSRP
$399
$349
$279
$169 / $199
$399
$199 / $229

Analysis

Radeon RX 5600 XT is based on the same Navi 10 die and RDNA architecture as the RX 5700 and XT parts. That means it's intrinsically expensive to produce, as the 10.3bn transistor die and 7nm production are costly. This point is worth remembering as we go further into the review.

It is closest to the RX 5700 from a top-end perspective; both cards share the same 36-CU (2,304-shader) setup, alongside 144 texture units and 64 ROPs. AMD does reduce the frequencies by a reasonable degree, to 1,375MHz game and 1,560MHz boost clock. The reason for doing so, of course, is to make use of Navi 10 dies that can't make the 5700 or 5700 XT frequency grade at acceptable voltages.

A diminution in frequency leads to an 11 percent reduction in GFLOPS throughput, but that's entirely okay for a card further down the stack. The far bigger change, and one likely to cause the greatest bottleneck, rests with the decision to drop the 256-bit, 14Gbps memory bus and speed in favour of 192-bit, 12Gbps. That's not all, though, as choosing this narrower width also has the knock-on effect of reducing the framebuffer from 8GB to 6GB. The numbers speak for themselves, as the RX 5700 enjoys 55 percent higher peak memory bandwidth and a 33 percent larger pool of onboard memory.

Reasonable reduction in GFLOPS allied to a rather meaty chop in bandwidth and size enables the RX 5600 XT to hit a more amenable 150W TDP, and we ought to see a bevy of cards using smaller form factors and a solitary 8-pin power connector. AIBs being what they are, that sage advice may well be ignored in favour of repurposing existing RX 5700/XT coolers and PCBs in the name of easy transitioning.

AMD and Nvidia can choose to construct GPUs how they wish - either by going for a new, custom Asic or lopping-off cores/frequency/bandwidth from extant designs - but the key drivers are price and, consequently, how the new GPUs fits into the wider landscape.

Expect to see cards ship today priced from $279 (£249). Reviewer literature compares RX 5600 XT to the GeForce GTX 1660 Super and shows it to be comfortably faster at 1080p. That, however, is not the correct financial comparison any more. Nvidia has since reduced the price of the RTX 2060 (non-Super), and such a move has, late last week, caused mild panic in AMD's ranks. Let's explain why.

The 11th Hour Mess - To OC or not OC

AMD doesn't want to reduce the pricing of the RX 5600 XT because that would erode profit margins for everyone in the chain, especially as this GPU is built from the relatively large RX 5700 die. That being the case, and the RTX 2060 arguably faster at the same sort of price, AMD's quandary is solved by tapping into the Navi 10 die for extra performance. And by extra, we mean a healthy dollop on core and memory.

For example, our review card, the Sapphire RX 5600 XT Pulse OC, was shipped to us with a boost clock of 1,620MHz and memory running at 12Gbps - or reasonably close to the base RX 5600 XT's specification. Given that Sapphire is using good silicon for its Pulse, and an excellent cooler, the decision was made by AMD to push the frequencies of this already-overclocked GPU. A new vBIOS cranked the GPU boost speed to 1,750MHz and, most importantly, the memory from 12Gbps to 14Gbps. The sum of these two changes increased performance by approximately 10 per cent, thereby placing the Pulse OC (Plus) into a better light against Nvidia's price-cut RTX 2060 rival.

The problem with this approach, so late in the day, is two-fold. The first is that most cards will have already shipped into the channel, so obtaining these new speeds requires end-users to manually flash their cards. Not a problem for seasoned enthusiasts, but certainly an impediment to those new or upgrading for the first time. Not good.

The second problem is that cranking up frequencies also raises power, and AMD has accordingly raised the total graphics power (TGP) from, say, 160W on an OC card up to 180W, calling cooling into question. PowerColor, for example, is now releasing its OC card, primed for these higher speeds, with an uprated cooler.

Point is, AMD was caught on the hop by Nvidia's recent price drop to the RTX 2060. Rather than reduce price, it has instructed add-in board partners to increase speeds, making RX 5600 XT OC cards even more like the RX 5700. Having covered the tech industry for almost 20 years, these late-in-the-day moves are some of the most haphazard I've seen. Yet if reducing pricing is out of the question, what else could AMD have done to make the RX 5600 more attractive? That's a hard one. Certainly, if Nvidia had been changing specifications last minute and sending out performance BIOSes, it would have been duly lambasted; so should AMD.

Summary

The Radeon RX 5600 XT, based on the Navi 10 die, arrives at retail in two flavours. The basic model, starting at $279, offers around 80 per cent of the RX 5700's performance while the OC card, now sporting faster memory and core speeds, ought to achieve 90 per cent of its performance. Pricing will be key in the inevitable comparison against GTX 1660 Super and Ti at the low end and the price-reduced RTX 2060 for OC models.