Sapphire Radeon RX Vega 64 - small review

Sapphire Radeon RX Vega 64

During the new year discounts period I have bought myself an RX Vega 64 from NewEgg.com - SAPPHIRE Radeon RX Vega 64 DirectX 12 21275-03-20G 8GB 2048-Bit HBM2 PCI Express 3.0 CrossFireX Support Video Card.

NewEgg package with Threadripper 1950x, RX Vega 64, Gigabyte x399 Aorus Pro, DDR4-3000 G.Skill TridentZ 64 GB

Previously I was using GeForce® GTX 1070 Super JetStream and it's performance was just not enough for comfortable gaming at 1440p, also I plan to get a FreeSync monitor in the future. Thus, I thought that RX Vega is going to provide me that much needed 15-20% better performance, and play nicely with the future FreeSync monitor.

I knew, that you should never buy a reference model of a GPU, but the price drop to just 360E convinced me to give it a try. There are numerous reviews about the card, and I knew that it's going to sound like a helicopter while working as a mini-heater.

When my RX Vega 64 arrived and I gave it a try, I had somehow mixing feelings. The frame rates (FPS) were definitely higher compared to GTX 1070, but every now and then there were some stutters, which were not even registered by FRAPS.

First, I tried to ignore it, but eventually, it was enough, the stutters were there, and the longer I play the more stuttery the game play was. It was time for some investigation.

The investigation

First thing first, I downloaded and installed latest AMD Radeon drivers, MSI Afterburner, HWiNFO, HWMonitor, then started to monitor my GPU's behavior.

There were sudden drops in GPU and HBM Memory clocks for every game stutter. It was very annoying. The GPU was dropping clocks for no good or obvious reason, it was not even overclocked, and the GPU temperature was under 65C, still, every now and then the operation frequency of GPU and HBM Memory was dropping to something like 100-200MHz.

After a night of debugging, undervolting, overclocking, and downclocking GPU and HBM Memory, I still had the sudden stutters caused by frequency drops. Of course, I have read many discussions and other threads about such or similar issue, nothing helped.

I even created a thread on tomshardware.co.uk - RX Vega 64 randomly drops GPU & RAM clock, but none replied.

The issue

It was 7am in the morning, when I remembered about the good old GPU-Z.

With readings from the GPU-Z Sensors tab I was able to identify the issue:

  • HBM Memory was warming up significantly higher than the GPU itself.
  • There were sudden HBM Memory temperature spikes to 99C, which were the reason for frequency drops.
  • A few times the HBM Memory temperature stroke to whopping 1500C, of course it was a reading error.

My theory was that the thermal compound is poorly applied on the HBM Memory side of the GPU. I downclocked and downvolted the HBM Memory, and voila, the temperature spikes along with the stutters almost disappeared!

The solution

To fix the problem, I had to re-apply the thermal paste on the GPU and the HBM Memory dies, luckily I had almost a full tube of Noctua NH-H1 lying around after my NH-U12S TR4-SP3 purchase.

There was a little problem though, that tiny white Warranty void if removed sticker, but come on, what kind of engineer you are if such stickers scare you off?

RX Vega 64 backplate

The GPU was disassembled, the thermal paste was re-applied, and the GPU was installed back into the system.

The original thermal paste was very dry and I felt like it was not enough of it.

The result

With the new thermal paste there is no more sudden temperature spikes, and almost no in game stutters. I am saying almost, because I have not yet played enough to validate.

I experienced some stutters while playing Battlefield 5, but it happened only a few times and during very intense multi player battles, so it might have been caused by something else.

AMD Radeon Wattman configuration

So far, the best configuration for my RX Vega 64 was as following:

  • Downvolt the GPU STATE 6 and STATE 7 to 1100 and 1130 mV.
  • Downvolt the Memory STATE 3 MAX to 1025 mV.
  • Increase the Fan speed to 400-4500 RPM.
  • Increase the Temperature Target to 85.
  • Increase the Power Limit to 40%.

The GPU is able to maintain constant clock speed of ~1550 MHz and the temperature stays at ~65C.

RX Vega 64 Wattman settings

The conclusion

If you are looking for a seamless experience then the reference design of RX Vega 64 is probably not for you. You will be better with something like Asus ROG Strix RX Vega 64, Sapphire Radeon RX Vega 64 Nitro+, or Gigabyte Radeon RX Vega 64 Gaming OC.

On the other hand, if you are looking for some cheaper deals, and enjoying tweaking hardware yourself, also not afraid of losing the warranty, then I wish you good luck on this difficult, but fun journey.

For myself

As long as the GPU works well, I don't mind spending some extra time tuning and tweaking it, extra heat and noise is not a problem for me either. I am well aware of how much pointless multi GPU setup nowadays is, but I still might get myself another RX Vega 64 for a CrossFire setup.

Vega 64 crossfire scaling testing in 24 games & 5 benchmarks.

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