So the number one question I am getting asked about the Xperia 1V is, has Sony resolved the overheating issue that some people experienced on the Mark 4?

The answer to that question on paper is yes. The Mark V's cooling chamber is approximately 60% larger, and the Mark V is rocking the new Snapdragon 8 gen 2, which is 45% more power efficient than the one seen in the Mark V. But the reality is…We don't know how this translates to real-world thermal performance. And I haven't seen any YouTube videos where someone tests the theory.

And that's precisely why I'm made this video. Because I like you, I want to see it for myself.

BEFORE THE TEST - CHARGING THERMALS

The first test is the 3Dmark Wildlife Extreme test. It pushes the CPU & and, more specifically, the GPU to the limits and will attempt to max out the frame rates and graphics over 25 mins.

I took initial readings. You'll see heat coming from the charging ports because I charged both devices 100% before running these tests. The max temperature of the mark V is 34.8, and it's really the centre temperature you want to watch because this is where the heat will be dissipated across. That's resting at 27.7 degrees.

The Mark IV got hotter during charging or maybe just dissipated the heat more slowly. The max temp at 37.4 is nearly 3 degrees hotter than mark V, and the center temperature is cooler by 0.5 degrees.

Okay, let's start the test & I'll speed it up, and we'll check in on the thermals periodically.

WILDLIFE EXTREME STRESS TEST

Okay, here is the first thermal reading around a third of the way through the test on mark 5. It's getting hot at 47.4 in the top corner and 40.7 in the centre. Now, it's good that the center temperature is rising. This means the heat is spreading evenly across the cooling surface. The larger the spread of heat, the quicker the device can cool.

Now let's compare this to the mark IV. Now, I bet you didn't see this coming. 43.5 max temperature, that's nearly 5 degrees cooler and 38.9 centre temperature.

You might be wondering how is this possible? I thought the Mark IV was prone to overheating. What we are seeing here is that Sony has put some software safety measures in place.

Possibly pre-emptive thermal throttling?

If you look at the FPS during the test, you'll notice that frame rates on the Mark V are running nearly double.

Second check

On second reading. The temperature on mark V is holding at 47.5, and centre temperature has risen to 42.6 degrees.

The heat travels to the centre of the device, which is good. The Mark IV is still running cooler at 44.5. Something tells me the performance throttling is kicking in at 45 degrees to protect the chip

- Result

Okay, here's the final result & on completion, the Mark V quickly returns to sun 45 degrees and the performance stability score is 56.2 per cent.

The mark V remains at 44 degrees with a 50.4 stability score. You can see that the performance range is massively different, and that's because the Mark V can ram faster and hotter without risking damage by overheating.

4K 120FPS RECORDING TEST

Gaming and graphics are one good way to make a phone overheat, but the best way, without a doubt, is to film 4K. And in the case of the Xperia 1 devices, filming in 4K 120fps will put these two phones under massive pressure.

And it's important to remember that not many phones out there can even shoot 4K 120. So, this test is unique to the Sony devices.

Okay, so here is a quick reading before filming the 4k 120 frames. The center temp on mark V is 34 degrees. Notice how there are no particular hot spots on the device. That's the improved cooling in action. On the mark IV, it's 33.6. But it's still Holding a lot of heat in the top at 38.8 degrees.

Let's start rolling

- Check 1

So you can see the Mark IV is showing the thermal warning icon, which proves my thermal that the Mark V has safety measures for reaching temperatures over 45 degrees. Temperature currently sits at 45.8.

The mark V has a similar temperature but now warning because the mark V can handle the heat better.

- Mark IV overheat time 10:06

Okay, so I took this reading before the mark V stopped filming due to thermals. 48 degrees is the cut-off point; you can see an 8-degree difference between the centre and the max temperatures. It recorded 4k 120 for 10:06 straight…which, to be honest, is really quite impressive.

- Mark V overheat time 17:15

I continued the test with the Mark V to see how much longer is could record for 17:15 before needing to shut down max temperature again around 48 degrees and 41.6 at the centre.

So now we have a definitive answer. Yes, the Xperia 1V is significantly better than the Mark IV regarding thermal efficiency. And even though at times the Snapdragons ran at similar temperatures. The handling of the high temperatures is approximately 58.8% better on the mark 5, and that's a significant upgrade.

And also consider this. The new Snapdragon 8 Gen 2 chip can run at better speeds and Frame rates and produce better graphics whilst running at high temperatures, so that's one of the reasons.

But another is that the improved cooling chamber in the Mark V dissipates heat faster, which means it doesn't necessarily need to run cooler because it can be pushed further because it handles the heat much more efficiently than before.

It is calm and cool under pressure.