Do you only use the PC for gaming?
I'd suggest something like this:
AMD Ryzen 9 7900 Twelve Core 5.40GHz (Socket AM5) Processor - Retail - £439.99
Gigabyte X670 Aorus Elite AX (Socket AM5) DDR5 ATX Motherboard - £350.00
Kingston FURY Beast EXPO 32GB (2x16GB) DDR5 PC5-48000C36 6000MHz Dual Channel Kit (KF560C36BBEK2-32) - £139.99
2x WD Black SN770 2TB SSD M.2 2280 NVME PCI-E Gen4 Solid State Drive (WDS200T3X0E) - £136.99
Zotac GeForce RTX 4090 Trinity 24GB GDDR6X PCI-Express Graphics Card - £1,699.99
Arctic Liquid Freezer II High Performance CPU Water Cooler - 420mm - £129.95
MSI MPG A1000G PCIE5 UK PSU 1000W 80 Plus Gold Power Supply - £219.95
Grand Total: £3,261.84
CPU: swap the 7900 CPU in my spec for the 7800X3D. I don't think 16 cores is necessary if you're only gaming, but I guess if you play the kind of game that is more inclined toward that, it might make more sense for you.
Motherboard: The price of the Extreme is just.. outrageous. Do you know which features it has you really want/need? If you can't answer that, I'd get a more modest board, especially as the 7800X3D doesn't need much.
PSU: I could be mistaken, but I don't think the TX 1300 is one of the newer ATX 3.0 & 12/16 pin PSUs, so I'd rather get something like the Thor II 1000 if I wanted high efficiency, but my choice would be the A1000G. I haven't done the calculations lately and never did them for high efficiency, high wattage PSUs, so can't comment on the current longer-term value of Gold vs Titanium/Platinum. If you mention your usage (e.g. time gaming and idle at desktop, average hours per day), I can try to give it a go.
SSDs: The SN850X is no longer on offer, unfortunately, so I'd just go with the SN770, unless your drives are heavy usage.
Cooler: Not sure what cooler fits or is optimal for your case?
