Mnementh said:
curl-6 said:
Wii U's CPU (Espresso) was sacrificed on the altar of backwards compatibility and power consumption. In order for it to natively play Wii games they stuck with the exact same architecture, which dated back to the Gamecube, and in order to keep power use to a minimum they kept its clocks quite low.
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That post makes no sense at all. The PS4 uses the x86 CPU-architecture, that dates back to 1978, and even then was built with some backwards compatibility to the 8080. The age of an architecture doesn't matter, if the CPUs in the line are updated with modern technology, which is true for PowerPC (the base for GC, Wii, WiiU, PS3 and XB360), Arm (base for Switch) or x86 (PS4, XB1).
Low power doesn't make sense as well. The Wii and the Switch targeted low power and were/are wildly successful.
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Wii U's CPU wasn't "updated with modern technology" though, it used the same PPC750 cores as Wii/GC, just three of them instead of 1, upclocked to 1.2GHz and with more cache.
Pemalite said:
curl-6 said:
Yeah, the more CPU-taxing Wii U games like (I assume) BOTW and Hyrule Warriors do run a lot better on Switch.
What is it that makes the A57s in the Switch better than Espresso, the fact that it's 64-bit versus 32-bit plus superscalar parallelism?
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64-bit vs 32-bit registers really aren't making a massive difference to performance there.
Having an extra CPU core, larger L1 cache, improved branch predictor, more capable integer and floating point engines, instruction buffers, 64-128-bit SIMD verses 2x 32-bit SIMD on WiiU... And more.
So despite the Switch's CPU having around the same clockrate, no eSRAM/eDRAM to act as an L3/L4 cache, only 3-way rather than 4-way... 18-long pipeline verses 4-7, It's design is far more balanced and the architecture is designed around more modern workloads which results in a significant uplift in CPU performance. (On the note of Pipeline length, ARM A57's pipeline is a variable length, so some workloads will only load up a couple stages.)
Which is why looking at plain black and white numbers never tells the entire story. (Bits, Flops, Mhz)
Espresso at the end of the day is a derivative from a design that existed in the 90's, where-as ARM A57 is a design that is far more modern and balanced.
But it just puts into perspective how bad IBM PowerPC really was, even the Cell was nothing special when compared to modern contemporary ARM/x86 designs, but they were extremely cheap.
The shortfall with the WiiU's CPU was indeed clockrate though.
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I read that one of Switch's CPU cores is reserved for running the OS/system functions though, so wouldn't that make it 3 cores vs 3 cores when it comes to games?
Not sure what games would be the best examples of Switch's CPU capability, but Witcher 3 I can't see running on Espresso. (Not to mention Wii U's weaker GPU and mere 1GB of RAM)
