gamerk316 :
szatkus :
Fact 1. i3-3220 is 20-28% faster in SINGLE THREAD.
Fact 2. Kaveri will struggle with Haswell parts: +10%
Fact 3. i5 has turbo: +15%
Fact 4. i5 has 4 true cores, Kaveri only 2 modules.
Conclusion: Kaveri can fight with i3, but has no chance with i5.
Missing a few key points though: While the module design has overhead, it looks like AMD is addressing the worst of it. Figure maybe 5% performance loss over a "true" independent core, already factored into IPC. So from a performance perspective, Fact 4 repeats fact 1.
I've checked some benchmarks which has single and multithreaded versions and it usually scales worse than Phenom II X4 or i5. AMD's 80% figure is correct.
gamerk316 :
Secondly, AMD has a form of Turbo too. And its hard to predict when/how long it kicks in. For those reasons, I typically disregard Turbo when doing calculations.
True, but I think it's safe to assume that for single thread both CPUs work on turbo clock.
gamerk316 :
Thirdly, clock is a factor. You can overcome a ~30% IPC deficit by clocking 30% higher. Which is the approach AMD is taking. The downside, however, is we still have heat concerns much above 4GHz, so that approach won't be able to drive performance improvements long term. Short term though, the extra clock is hiding the IPC deficit.
But Steamroller clock won't be much higher than Piledriver's. 2-5%, I think.
gamerk316 :
Performance wise? SR is probably going to be close to SB at clocks around 4.5GHz or so, which it looks like AMD will hit. OCing will obviously be limited though, so we'll still have our discussions over which is "better". SR is basically what BD should have been when it was launched.
I agree with that, but it's still not enough to defeat i5 IB with just 2 SR modules.
gamerk316 :
One final point: Everyone here is overblowing HSA. Big time.
Because people which write in topic with "AMD" in title usually like AMD. Because of that they usually overestimate some things...