I wonder how heavily dI/dt events weighed on Intel in deciding to integrate the voltage regulator on-die in Haswell?<p>Tech Report [1] says the FIVR (Fully Integrated Voltage Regulator) is for:<p>• higher efficiency, lower voltage ripple<p>• cleaner power delivery [closer to the load, and controlled by Intel]<p>• very high frequency, to 140 MHz. This one seems relevant, reacting faster to dI/dt events<p>• the only apparent downside is that with more things in one package the thermal load is higher, but bear in mind haswell's very low overall power usage<p>[1] <a href="http://techreport.com/news/24802/leaked-slides-expose-haswell-integrated-voltage-regulator" rel="nofollow">http://techreport.com/news/24802/leaked-slides-expose-haswel...</a>
This is just the start. Next phase is to over clock while transistor error budget is within bounds, need to have heat and error sensors all over the die.<p>The other one is having functional instruction packet transactions that they can retry somewhere else if they fail during processing.<p>With these changes, the CPUs will always be operating at some pre determined error rate regime. No more over clocking, just change the AER (allowable error rate) register, which also will be a thing for simulations that don't matter like games and that do matter like Excel handling your payroll.
<i>6. Microarchitectural throttling to reduce current draw (e.g., Itanium processors issue fewer instructions during dI/dt events and vector units often take many cycles to ‘warm up’); this reduces IPC and can cause instruction scheduling challenges.</i><p>How literal is the 'warm up' for the vector units? I've occasionally seen this effect mentioned with regard to microbenchmarking, but never understood why this might be. Are vector units actually slowly activated over several cycles so as to reduce voltage droop?
Not explicitly referring to the article, but it really saddens me that RWT is no longer going to get the extremely detailed articles it used to with the writers partial transition to the MPR. I'm happy for him, but at the same time I can't justify $800/yr towards good articles as someone who only follows the industry from a hobbyist perspective.