with fast ram. That pretty much means additional accelerator card because Commodore didnt bother to build fast ram memory controller into the thing. You couldnt just slap some simms or ram chips on a card, you needed additional logic. Cheapest contemporary Fast Ram cards were ~100 pounds + ~30 pounds a meg, half the cost of 270 pound Amiga A1200 in 1994. You could argue it still cheaper than PC, lets count.
And after all that, you'd still have a 68020 under the hood. You could, of course, spend an eye-watering amount of money on a 68040 accelerator... and then... you're still not going to beat the DX2/66. (Let's not even talk about the performance of AGA versus a local bus SVGA card)
It feels like I've heard so many Amiga users say that they finally broke down and jumped ship when Doom and the DX2/66 dropped. It really was a gamechanger. Before then it was possible to argue that a '040 Amiga 4000 still held its own against a DX/33 or maybe even a DX/50, but not this.
There were a lot of things that came together to kill the Amiga, mostly Commodore's mismanagement, mismarketing and complacency, but as the final blow to it being a viable computer with a future in the eyes of consumers, I feel like the DX2/66 was it. It would have killed the Mac too if Apple hadn't woken up to smell the coffee a few years prior and had Power Macs ready to go.
Back in the day, I was playing DooM 2 on a 386DX 40MHz and was very fine. And Rebel Assault on 14fps.
Also, I managed to play DooM 3 on a GeForce 2 MX DDR (using the patch sets to allow it to run on Voodo cards).