Splave's Cave: Overclocking the Asus RTX 5090 Astral and setting the 3DMark Port Royal world record

Welcome, my name's Splave, or Allen Golibersuch, and I am a professional overclocker. You may have read some of my previous articles on Tom's Hardware, or spotted me in a YouTube video or two. In this column, I will delve into extreme overclocking and muse about what it's like to run your own bespoke system integrator business. But first of all, if you're not acquainted with who I am or what I do, here's an introduction.

For me, overclocking started as just a hobby, but a fairly serious one. I would jet across the world to events like Computex and other live events, winning or placing across overclocking competitions. Unfortunately, not many places or people were willing to pay folks to overclock hardware. Shocking, I know. After some experimentation with launching my own bespoke PC, I knew that I didn't ever want to just sell normal PCs. I wanted to make performance computers that are better than what's out there for a similar price, where my overclocking talents could be used as an added benefit, not merely a pricing burden.

That's when a company I had a long-time relationship with approached me, and asked if they could take a percentage share of ownership and invest in launching my own brand of PCs. It all initially started as a very boutique operation, but eventually rolled over into a full-on system integrator, which is where I am today. Do you know how many Fractal Design cases you can fit into a garage? Asking for a friend.

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Anyway, at this point, building and tinkering with PCs isn't just my hobby, or my work, it's my love. I hope you enjoy the forthcoming columns on Tom's Hardware Premium, where I get a chance to stretch my legs and wax lyrical about the things I love.

For the inaugural edition of Splave's Cave, I pick apart a very special graphics card, the Asus ROG Astral RTX 5090. Yes, the 5090 came out months ago, and yes, there is a gold version, which I sadly do not own. But while the GPU I'm using isn't made of real gold, it's capable of capturing world-record gold. Here's how I set a 3DMark Port Royal World Record. Don't catch your fingers on that silicon, because it's about to get cold.

While I hate to be late to the party, a lot of work goes into overclocking top-tier hardware. Luckily, Asus has crafted an incredibly performant graphics card, with excellent R&D and overclocking departments that work hard on providing workarounds for the protections that any GPU might have. Yeah, those protections, the ones that make sure that the cards don't go boom or catch fire. We're finally in a place where those protections have extended far enough that we can pull out some wild performance from these GPUs at sub-ambient temperatures.

But, there is one thing: You can't try this specific technique at home. I am using a special, non-public BIOS for the GPU that offers a much higher power limit than the standard one would allow. I want to be fully transparent about this, and I'm sorry, but if you want to acquire the BIOS, it's not mine to give out. With that in mind, I know what I am doing, and I am fully prepared to smoke an incredibly expensive graphics card.

There are still challenges without power limits

Equipped with the bespoke BIOS, another challenge awaits. Even if the GPU's standard power limits are removed, thermal limits remain a bottleneck. If you let your card get super hot, it's going to still lower its clock speed in an attempt to avoid outright failure. So, this bespoke BIOS with its extended power limits is practically useless without sub-ambient cooling. For the standard OC BIOS, there's plenty of headroom, which the ROG Astral RTX 5090's cooler is equipped to handle; many cards can run +2000 MHz memory speeds without additional cooling, which is a feat of engineering in itself.

Simply put, the card is incredible. I've been doing this for a long time, and Asus' latest effort is head-and-shoulders above the next-best card I have touched. I'm not trying to wax lyrical about Asus because I am "glazing," as the kids like to say; they've really earned it, and I have nothing negative to say about it at all. The GPU is heavy because the cooler is so well designed. It commands a pricing premium because the components used within it are premium. It runs quietly and looks elegant and discreet. The Asus ROG Astral 5090 just shows up and does work; it's a real powerhouse of a GPU.

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The 5090 die doesn't like being cold

Despite all of that fantastic engineering and being equipped with a custom BIOS, the GPU hates being cold. When using liquid nitrogen (LN2) cooling, the ROG Astral RTX 5090 starts misbehaving at around -10°C to -20°C. By misbehaving, I mean that the screen goes black, the system hangs, and you have to wait until the card is above 0°C before you can boot it back into Windows — otherwise known as a 'cold bug.'

This is one of those situations where I just have to take a step back, take a deep breath, turn around toward my punching bag, and away from the expensive electronics, to let off some steam for a few minutes.

But, not liking the cold isn't an issue specific to Asus' ROG Astral 5090; it's an Nvidia issue. The RTX 5090 die itself doesn't like being cold, with users of other brands reporting similar experiences. Situations like this make me feel like we could really use a Kingpin right about now. He always had a way to finesse Nvidia into fixing cold bug issues, which isn't something a basement hobbyist can achieve.

Impressive results, despite limitations

But, with that being said, the ROG Astral RTX 5090 can still pull off some pretty impressive feats, without reaching extremely cold temperatures; this card could hit core clock speeds of 3600MHz+.

For comparison, the Asus ROG Matrix 4090, the first GPU to run at over 4 GHz, required cooling down to -190°C to accomplish that feat. Now, just imagine if the RTX 5090 could come close to running at those temperatures, it would simply be absurd. I know that Asus is exploring ways to overcome the cold limits of the RTX 5090 die, and I'll keep testing the new BIOSes they send my way. Hopefully, any amount of additional cold temperature tolerance will yield even greater results.

Meanwhile, with the card safely idling at -20°C, the ROG Astral RTX 5090 demands over 1,000 watts of power when you start a benchmark. This spikes the temperature from -20°C to +10°C instantly, and that's with a five-pound copper pot filled with LN2 attached to it. Whatever the case may be with the cold, the GPU has significant thermal demands, given the amount of power it's sucking up.

This can be tricky to maintain throughout the benchmarking process. If the benchmark ends before you taper down on pouring the LN2, it will drop from +20°C all the way to -50°C instantly when there is no load. That means more black screens, more time waiting to get it back to 0°C, and yes, you'll have to start over and attempt the benchmark again. Needless to say, that punching bag I mentioned earlier is getting a lot of use.

Regardless of all those headaches, once you manage to figure out the perfect cocktail of pouring the LN2 throughout the benchmark, and you see the score pop up, it makes the entire effort worthwhile. After a good amount of trial and error, I was able to set a 3DMark Port Royal record with a score over 48,000. A standard RTX 5090 usually achieves around 35,000.

Additionally, I achieved the GPUPI 32B world record and both Unigine Superposition records with the 1080p and 8K configs. These were achieved a little while ago, so it's likely that you'll spot me elsewhere on the leaderboards, too.

That about wraps it up for the first edition of Splave's Cave on Tom's Hardware Premium. Coming up next will be a guide on how to actually set yourself up for extreme overclocking, with a similar setup to the images posted in the article. Keep your eyes peeled, and thanks for reading.