A520 Motherboard Torture Test with Ryzen 9
Beside me is an A520 motherboard, specifically the Asus A520M-K provided by AWD-IT, there will be a link to it in the description below if you are interested. Now you would be forgiven for never having heard of “A520” before, it’s AMD’s lowest end chipset and it’s mostly ignored by us enthusiasts – but for good reason. Just look at this thing. It’s as bare as a desert, only offering two RAM slots, a lonely AM4 socket in the middle, a single PCIe x16 slot and no VRM heatsinks in sight.
The A520 chipset is the most basic. It doesn’t offer direct overclocking support (although does let you set your memory to any speed you like… cough intel cough). Anyway, it’s really simple. AMD CPUs are effectively SOCs – system on chip – basically that means all the controllers the chip needs to function are built into the CPU itself, so the memory controller for the RAM, PCIe controller for storage and graphics, and even a USB controller. So, the chipset, especially the A520 one, acts kind of like a USB hub does, but for PCIe. It lets you connect some extra USB ports, and a few SATA devices alongside a touch more PCIe lanes but that’s about it.
It’s capped at PCIe Gen 3, so despite supporting both Ryzen 3000 and 5000 series CPUs, you won’t be able to use Gen 4 anywhere here. The link to the chipset is the same as B550, PCIe gen 3 x4 and the 16 direct lanes don’t support bifurcation like B550 does – so no multi-GPU. Shame I know..
Interestingly though, despite direct overclocking being unavailable, Precision Boost Overdrive is still there. You can set it up in the BIOS just as you would on a B550 or X570 board, although I won’t be testing with it in this video for one very good reason I will explain shortly…
Really though, the VRMs are the main point of contention here. This is, as best as I can tell, a doubled 4+2 setup, although I’m not knowledgeable enough on VRM designs to say for sure. What I do know is the MOSFETs, the things switch on and off to decrease the voltage from 12V from the PSU to the 1.3-1.45V the CPU needs, they aren’t the best. They are technically rated for 60A, but a closer look at the datasheet reveals their current capacity dwindles significantly with rising temperature. In theory, this should be capable of supplying double, if not quadruple, the amount of power this 5900X I’ll be testing with will require. In practice… I’m not so sure.
So, testing with a 5900X.. On a £60 motherboard. Something just doesn’t feel right about this. Now the tests that I ran weren’t just to see how quickly it would catch fire, but instead my full suite of benchmarks to see just how much performance you drop from having lackluster VRMs powering your high end CPU.
To that end, the A520 board offered 2% less performance in Cinebench R20 single threaded. That’s actually not something I expected as single threaded workloads are rather light on a CPU, so there is a lot of power budget available to let it boost to its maximum. In multi-threaded it’s actually slightly less bad, with 1.8% slower rather than 2.2% on single. Again, that’s rather surprising, until you realise the render time. See, Cinebench’s mutli threaded render normally takes around 30 seconds or so with a 5900X.
That’s not much, as when we switch to a longer 2 minute render in Blender, using the BMW scene, well, it’s 11 seconds slower or 8% on the A520 board compared to B550. That’s a pretty big deal as you are leaving a good chunk of performance on the table with your ultra-cheap board.
But what happens when it’s a really long render though? Oh boy. Using the Gooseberry scene which takes around 9 minutes on a 5900X, well it took 12 minutes using an A520 board. That’s 30% slower, or about as slow as buying a 5800X instead. Interestingly, when I let the VRMs cool down, then re-ran the test, it actually came back faster at 10 and a half minutes, rather than 12m 15s, but that makes it abundantly clear the VRMs aren’t really suited to run this – they can, but they shouldn’t.
If you are interested, here are the Adobe CC suite app results using Puget Bench. A slight drop across the board here, but nothing too insane.
But what about gaming? Well, in Watchdogs Legion at 1080p ultra settings with the same GPU and RAM speed, we are getting 4 FPS average less. It’s not much, but I generally don’t see much FPS loss from this game, so to see 4 gone is actually quite surprising.
In Cyberpunk again at ultra settings it’s 6 FPS average less. Still not enough to really notice in game, but the 1% lows dropping 6 FPS too, that’s one you might feel while playing, and knowing you are losing around 6% of your performance might make you reconsider your buying choice.
Finally in Fortnite it’s pretty minimal, just 3 FPS lost here, really nothing to worry about.
The reason why there isn’t a massive loss in games is that most games just aren’t pushing large core count chips like this very hard. They load a few cores but nothing major, so the VRMs were able to keep up and stayed relatively cool – at least by their standards. What temperature you ask? Around 80°c. Yeah. That’s hotter than most B550 boards I’ve used get under full 100% CPU load – yet this setup hits that while gaming. Want to know what the maximum temperature I recorded them hitting while rendering in Blender was? You’ll want to be sitting for this. 120°c. Cooked egg anyone?
You would be right to assume this was a bit of a fire hazard, and that it’s dangerous in general. The good news is, at least according to the datasheet for the MOSFETs, 150°c is their thermal junction – maximum – temperature, and the board itself hit temperature limits and cut power while testing, so it is safe, and as long as you don’t let flammable material anywhere near them, you should be fine.
You could assist them by adding the same sort of stick on heatsink you get for raspberry pi’s, although I would be careful of them either soaking heat into the drivers and burning them out, or falling off and shorting the back of your GPU – so maybe don’t do that. In fact, maybe don’t run a 5900X on an A520 board. It’s a bad idea. If you are going to spend £600 on a CPU, maybe don’t spend literally 1/10th of that on the motherboard that powers it. Yes, technically you can. It’s safe and in theory shouldn’t ruin your nice new CPU, but in practice just pay a bit more and get a reasonable B550 board instead with heatsinks and VRMs that can handle 140W flowing through them.
