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>The big issue is that Intel has been stuck for so long My memory isn't so good, and I never owned a P4, but according to Wikipedia in August 2001, they releas
by perl4ever 6y ago
>The big issue is that Intel has been stuck for so long
My memory isn't so good, and I never owned a P4, but according to Wikipedia in August 2001, they released one at 2GHz on 180 nm. Almost 20 years later, my laptop i7 is running at...2.1GHz (base)? And 14 nm. That's kind of mind boggling. I think it would be interesting to read/write an article comparing the two in depth and what performance benefits you get from the newer chip.
- goalieca 6y agothere's a very widely used measure here in the academic community: instructions per cycle (ipc). IPC boils down to how many instructions can you actually complete per clock cycle once you account for memory, caching, etc.
- a1369209993 6y agoIIRC, that's maybe a 16x improvement (32x if you count 32->64 bit). Which accounts for less than half of the (orders of magnitude of) improvement we should have got from Moore's law. (More cores aren't a performance improvement; if you were willing to deal with non-serial execution, you could have just bought 32 Pentium Fours; putting them all on the same chip is convenient (and cheap), but as a price/performance improvement, it's all price, no performance.)
- blattimwind 6y ago> (More cores aren't a performance improvement; if you were willing to deal with non-serial execution, you could have just bought 32 Pentium Fours; putting them all on the same chip is convenient (and cheap), but as a price/performance improvement, it's all price, no performance.) That's only true if you only consider ALU throughput for performance, but in terms of real world performance, where the interconnect between cores and memory is hugely significant, a multicore processor has many advantages over a rack of otherwise equivalent single-core NUMA nodes.
- perl4ever 6y agoI was thinking single thread though. My guess is that there are now a lot of forms of hardware acceleration of specific things that make your daily experience seem faster, but I haven't seen them catalogued and put in perspective with measurements.
- Someone 6y agoSingle-threaded doesn’t imply IPC can’t go up or go above 1. See https://en.m.wikipedia.org/wiki/Superscalar_processor https://en.m.wikipedia.org/wiki/Superscalar_processor. I would think that and cache size are large differences between a P4 and the i7 running at about the same clock frequency.
- innocenat 6y agoi7 can regularly archive 2-3ipc easily. I haven't read about P4 and NetBurst in a long t ime, but is mu memory serve me right, P4 is usually less than 1ipc due to its very long pipeline (31 stages IIRC) that is very prone to pipeline stall. Modern processor can also do many thing faster. I think P4 takes ~110 cycles for integer division, while modern cpu can do in ~30-40 cycles. And IIRC, P4 cannot flush the division unit so if branch/jump prediction is wrong and division is speculated, it was to wait until the division unit finish computation before it can resume execution.
- IshKebab 6y agoYou can find benchmarks for CPUs going back to 2004 on PassMark: https://www.cpubenchmark.net/year-on-year.html https://www.cpubenchmark.net/year-on-year.html The frequencies may not have increased beyond 2-3 GHz but the speed has still got faster because modern processors are much smarter and are able to do more work per cycle. They have all sorts of fancy tricks to do that - speculative execution, hyperthreading, branch prediction, etc.
- pjmlp 6y agoExcept that instead of 1, now it has 4 CPUs and a GPGPU as part of it, GHz aren't everything, the problem is that most programs as still written single threaded.