Well a simple CPU is much more efficient then a complex one.
A modern AMD/intel uses very few gates to implement the arithmetic. we are talking ~1% of the gates actually do the work. The rest is taken up by Cashes, Schedulers, Branch predictors, Decoders, and a load of other stuff that is designed to speed up the CPU to get good single core performance. all this extra hardware takes up a lot of power.
Here is an interesting thought experiment:
On a large die you could (theoretically) today fit say one million Motorola 68000 Processors. If you clocked that at 5Ghz it would in theory be about 1000 times faster then a Ryzen 7 using the same power. But it would still mean that each core would be hundreds of times slower then a Ryzen core. It would be almost impossible to write programs that would utilize all one million cores effectively enough to make a program run faster on this hardware than it does on a Ryzen CPU.
Right now RISC-V is very simple this means it draws very little power. The problem is that it doesn't scale. The RISC-V instruction set is not one that makes it easy to add all the optimizations that one wants to add for a high performance CPU.
Its a bit like saying that an ant is more efficient than a bulldozer, yes, that's technically true, but trying to coordinating a million ants to build a road is a lot less efficient then just using a bulldozer.
A modern AMD/intel uses very few gates to implement the arithmetic. we are talking ~1% of the gates actually do the work. The rest is taken up by Cashes, Schedulers, Branch predictors, Decoders, and a load of other stuff that is designed to speed up the CPU to get good single core performance. all this extra hardware takes up a lot of power.
Here is an interesting thought experiment:
On a large die you could (theoretically) today fit say one million Motorola 68000 Processors. If you clocked that at 5Ghz it would in theory be about 1000 times faster then a Ryzen 7 using the same power. But it would still mean that each core would be hundreds of times slower then a Ryzen core. It would be almost impossible to write programs that would utilize all one million cores effectively enough to make a program run faster on this hardware than it does on a Ryzen CPU.
Right now RISC-V is very simple this means it draws very little power. The problem is that it doesn't scale. The RISC-V instruction set is not one that makes it easy to add all the optimizations that one wants to add for a high performance CPU.
Its a bit like saying that an ant is more efficient than a bulldozer, yes, that's technically true, but trying to coordinating a million ants to build a road is a lot less efficient then just using a bulldozer.