[Latest 2026] Should you buy RTX 5090/5080? Summary of evolution points from the 40 series and recommended power supply capacity

NVIDIA’s latest graphics board “GeForce RTX 50 series (Blackwell architecture)” has finally hit the market.
Some say that the price is too high and that the specifications are over the top, but when you actually run the benchmarks, you will be shocked at the difference in performance.
This time, we will thoroughly explain whether RTX 30/40 series users should switch, as well as the specific performance differences and points to note (especially electricity costs and size).

RTX 5090’s performance is “on a different level”

The flagship model RTX 5090 has improved performance by approximately 1.5 to 1.7 times compared to the previous generation 4090.
Of particular note are “AI processing performance” and “ray tracing performance”.

Even in heavy titles like Monster Hunter Wilds and GTA6, it is a monster spec that can hit “native 120fps” at 4K resolution and highest image quality setting.
With DLSS (AI upscaling), we have reached a level where even 8K gaming can be seen.

RTX 5080 is a realistic option

The favorite for many gamers is the RTX 5080.
This has performance equivalent to or better than the 4090, but consumes slightly less power (although it is still expensive).
This 5080 is the best buy for FPS enthusiasts who aim for 240Hz to 360Hz on a WQHD (2560×1440) monitor, and RPG enthusiasts who want to stabilize at 4K/60fps.

The biggest issues are “power supply” and “size”

Before purchasing the 50 series, you must definitely check the PC case and power supply unit.

1. Power capacity (ATX 3.1 対応)

Recommended power supply capacity is 1000W to 1200W for 5090, and 850W or more for 5080.
In addition, it is strongly recommended that you replace the power supply unit with an ATX 3.1 standard that supports the new “12V-2×6 connector” instead of the conventional 8-pin connector.
It is best to avoid using a conversion cable as there is a risk of melting due to poor contact.

2. Problems that do not fit into the case

Card size continues to grow larger.
It is not uncommon to find models that are 350mm long and occupy 4 slots.
Mini tower cases are almost completely wiped out. Please measure the space inside the case in millimeters with a tape measure before purchasing.

Summary: Who should buy it?

• RTX 5090: For 4K monitor users, people who generate AI images, and people who cannot live without the best.
• RTX 5080:People who don’t want to replace their GPU in the next 5 years.
• RTX 5070 or below:For Full HD to WQHD environments, waiting for the release in spring is the best option for cost performance.